Full Code of bjweimengshu/ProgrammerXiaohui for AI

Repository: bjweimengshu/ProgrammerXiaohui
Branch: master
Commit: 5f77405fbcca
Files: 33
Total size: 61.6 KB

Directory structure:
gitextract_79e5z20f/

├── README.md
└── src/
    ├── chapter1/
    │   ├── part2/
    │   │   └── TimeComplex.java
    │   └── part3/
    │       └── SpaceComplex.java
    ├── chapter2/
    │   ├── part1/
    │   │   └── MyArray.java
    │   ├── part2/
    │   │   └── MyLinkedList.java
    │   └── part3/
    │       └── MyQueue.java
    ├── chapter3/
    │   ├── part2/
    │   │   ├── BinaryTreeTraversal.java
    │   │   ├── BinaryTreeTraversalLevel.java
    │   │   └── BinaryTreeTraversalStack.java
    │   ├── part3/
    │   │   └── HeapOperator.java
    │   └── part4/
    │       └── PriorityQueue.java
    ├── chapter4/
    │   ├── part2/
    │   │   ├── BubbleSort.java
    │   │   └── CockTailSort.java
    │   ├── part3/
    │   │   ├── QuickSort.java
    │   │   └── QuickSortWithStack.java
    │   ├── part4/
    │   │   └── HeapSort.java
    │   └── part5/
    │       ├── BucketSort.java
    │       └── CountSort.java
    ├── chapter5/
    │   ├── part10/
    │   │   └── BigNumberSum.java
    │   ├── part11/
    │   │   └── GoldMining.java
    │   ├── part12/
    │   │   └── FindLostNum.java
    │   ├── part2/
    │   │   └── LinkedListCycle.java
    │   ├── part3/
    │   │   └── MinStack.java
    │   ├── part4/
    │   │   └── GreatestCommonDivisor.java
    │   ├── part5/
    │   │   └── PowerOf2.java
    │   ├── part6/
    │   │   └── MaxSortedDistance.java
    │   ├── part7/
    │   │   └── StackQueue.java
    │   ├── part8/
    │   │   └── FindNearestNumber.java
    │   └── part9/
    │       └── RemoveKDigits.java
    └── chapter6/
        ├── part2/
        │   └── MyBitmap.java
        ├── part3/
        │   └── LRUCache.java
        ├── part4/
        │   └── AStar.java
        └── part5/
            └── Redpackage.java

================================================
FILE CONTENTS
================================================

================================================
FILE: README.md
================================================
来到这里的朋友们，很高兴你们能看到小灰的拙作。
小灰把书中各个章节所涉及到的代码，都总结到了这个项目当中，让大家可以更方便地学习和调试。
小伙伴们对代码有哪些问题和意见，也欢迎向小灰提出，在这里感谢大家的支持！

最后，欢迎大家关注小灰的技术公众号，直接在微信上搜索 “程序员小灰” 即可看到。

祝大家在算法的道路上学有所成！

针对《漫画算法》的第一次印刷版本，小灰整理了一个勘误表，欢迎大家指正：http://mp.weixin.qq.com/s?__biz=MzIxMjE5MTE1Nw==&mid=505714242&idx=1&sn=59526f45b94db2f4be750273431e8867&chksm=0c99e4983bee6d8eb4beed7f6143bbbc00659f32056b37db1d3f1b925ca6867d7d2c34d6ad64#rd


================================================
FILE: src/chapter1/part2/TimeComplex.java
================================================
package chapter1.part2;

/**
 * Created by weimengshu on 2018/8/24.
 */
public class TimeComplex {

    void eat1(int n){
        for(int i=0; i<n; i++){;
            System.out.println("等待一天");
            System.out.println("等待一天");
            System.out.println("吃一寸面包");
        }
    }

    void eat2(int n){
        for(int i=n; i>1; i/=2){
            System.out.println("等待一天");
            System.out.println("等待一天");
            System.out.println("等待一天");
            System.out.println("等待一天");
            System.out.println("吃一半面包");
        }
    }

    void eat3(int n){
        System.out.println("等待一天");
        System.out.println("吃一个鸡腿");
    }

    void eat4(int n){
        for(int i=0; i<n; i++){
            for(int j=0; j<i; j++){
                System.out.println("等待一天");
            }
            System.out.println("吃一寸面包");
        }
    }
}


================================================
FILE: src/chapter1/part3/SpaceComplex.java
================================================
package chapter1.part3;

/**
 * Created by weimengshu on 2018/8/24.
 */
public class SpaceComplex {

    void fun1(int n){
        int var = 3;
        //do something
    }

    void fun2(int n){
        int[] array = new int[n];
        //do something
    }

    void fun3(int n){
        int[][] matrix = new int[n][n];
        //do something
    }

    void fun4(int n){
        if(n<=0){
            return;
        }
        fun4(n-1);
        //do something
    }
}


================================================
FILE: src/chapter2/part1/MyArray.java
================================================
package chapter2.part1;

/**
 * Created by weimengshu on 2018/8/24.
 */
public class MyArray {

    private int[] array;
    private int size;

    public MyArray(int capacity){
        this.array = new int[capacity];
        size = 0;
    }

    /**
     * 数组插入元素
     * @param index  插入的位置
     * @param element  插入的元素
     */
    public void insert(int index, int element) throws Exception {
        //判断访问下标是否超出范围
        if(index<0 || index>size){
            throw new IndexOutOfBoundsException("超出数组实际元素范围！");
        }
        //如果实际元素达到数组容量上线，数组扩容
        if(size >= array.length){
            resize();
        }
        //从右向左循环，逐个元素向右挪一位。
        for(int i=size-1; i>=index; i--){
            array[i+1] = array[i];
        }
        //腾出的位置放入新元素
        array[index] = element;
        size++;
    }

    /**
     * 数组扩容
     */
    public void resize(){
        int[] arrayNew = new int[array.length*2];
        //从旧数组拷贝到新数组
        System.arraycopy(array, 0, arrayNew, 0, array.length);
        array = arrayNew;
    }

    /**
     * 数组删除元素
     * @param index  删除的位置
     */
    public int delete(int index) throws Exception {
        //判断访问下标是否超出范围
        if(index<0 || index>=size){
            throw new IndexOutOfBoundsException("超出数组实际元素范围！");
        }
        int deletedElement = array[index];
        //从左向右循环，逐个元素向左挪一位。
        for(int i=index; i<size-1; i++){
            array[i] = array[i+1];
        }
        size--;
        return deletedElement;
    }

    /**
     * 输出数组
     */
    public void output(){
        for(int i=0; i<size; i++){
            System.out.println(array[i]);
        }
    }

    public static void main(String[] args) throws Exception {
        MyArray myArray = new MyArray(4);
        myArray.insert(0,3);
        myArray.insert(1,7);
        myArray.insert(2,9);
        myArray.insert(3,5);
        myArray.insert(1,6);
        myArray.insert(5,8);
        myArray.delete(3);
        myArray.output();
    }
}


================================================
FILE: src/chapter2/part2/MyLinkedList.java
================================================
package chapter2.part2;

/**
 * Created by weimengshu on 2018/8/24.
 */
public class MyLinkedList {

    //头节点指针
    private Node head;
    //尾节点指针
    private Node last;
    //链表实际长度
    private int size;

    /**
     * 链表插入元素
     * @param index  插入位置
     * @param data  插入元素
     */
    public void insert(int index, int data) throws Exception {
        if (index<0 || index>size) {
            throw new IndexOutOfBoundsException("超出链表节点范围！");
        }
        Node insertedNode = new Node(data);
        if(size == 0){
            //空链表
            head = insertedNode;
            last = insertedNode;
        } else if(index == 0){
            //插入头部
            insertedNode.next = head;
            head = insertedNode;
        }else if(size == index){
            //插入尾部
            last.next = insertedNode;
            last = insertedNode;
        }else {
            //插入中间
            Node prevNode = get(index-1);
            insertedNode.next = prevNode.next;
            prevNode.next = insertedNode;
        }
        size++;
    }

    /**
     * 链表删除元素
     * @param index  删除的位置
     */
    public Node remove(int index) throws Exception {
        if (index<0 || index>=size) {
            throw new IndexOutOfBoundsException("超出链表节点范围！");
        }
        Node removedNode = null;
        if(index == 0){
            //删除头节点
            removedNode = head;
            head = head.next;
            if(size == 1){
                last = null;
            }
        }else if(index == size-1){
            //删除尾节点
            Node prevNode = get(index-1);
            removedNode = prevNode.next;
            prevNode.next = null;
            last = prevNode;
        }else {
            //删除中间节点
            Node prevNode = get(index-1);
            Node nextNode = prevNode.next.next;
            removedNode = prevNode.next;
            prevNode.next = nextNode;
        }
        size--;
        return removedNode;
    }

    /**
     * 链表查找元素
     * @param index  查找的位置
     */
    public Node get(int index) throws Exception {
        if (index<0 || index>=size) {
            throw new IndexOutOfBoundsException("超出链表节点范围！");
        }
        Node temp = head;
        for(int i=0; i<index; i++){
            temp = temp.next;
        }
        return temp;
    }

    /**
     * 输出链表
     */
    public void output(){
        Node temp = head;
        while (temp!=null) {
            System.out.println(temp.data);
            temp = temp.next;
        }
    }

    /**
     * 链表节点
     */
    private static class Node {
        int data;
        Node next;

        Node(int data) {
            this.data = data;
        }
    }

    public static void main(String[] args) throws Exception {
        MyLinkedList myLinkedList = new MyLinkedList();
        myLinkedList.insert(0,3);
        myLinkedList.insert(0,4);
        myLinkedList.insert(2,9);
        myLinkedList.insert(3,5);
        myLinkedList.insert(1,6);
        myLinkedList.remove(0);
        myLinkedList.output();
    }
}


================================================
FILE: src/chapter2/part3/MyQueue.java
================================================
package chapter2.part3;

/**
 * Created by weimengshu on 2018/8/24.
 */
public class MyQueue {

    private int[] array;
    private int front;
    private int rear;

    public MyQueue(int capacity){
        this.array = new int[capacity];
    }

    /**
     * 入队
     * @param element  入队的元素
     */
    public void enQueue(int element) throws Exception {
        if((rear+1)%array.length == front){
            throw new Exception("队列已满！");
        }
        array[rear] = element;
        rear =(rear+1)%array.length;
    }

    /**
     * 出队
     */
    public int deQueue() throws Exception {
        if(rear == front){
            throw new Exception("队列已空！");
        }
        int deQueueElement = array[front];
        front =(front+1)%array.length;
        return deQueueElement;
    }

    /**
     * 输出队列
     */
    public void output(){
        for(int i=front; i!=rear; i=(i+1)%array.length){
            System.out.println(array[i]);
        }
    }

    public static void main(String[] args) throws Exception {
        MyQueue myQueue = new MyQueue(6);
        myQueue.enQueue(3);
        myQueue.enQueue(5);
        myQueue.enQueue(6);
        myQueue.enQueue(8);
        myQueue.enQueue(1);
        myQueue.deQueue();
        myQueue.deQueue();
        myQueue.deQueue();
        myQueue.enQueue(2);
        myQueue.enQueue(4);
        myQueue.enQueue(9);
        myQueue.output();
    }
}


================================================
FILE: src/chapter3/part2/BinaryTreeTraversal.java
================================================
package chapter3.part2;

import java.util.Arrays;
import java.util.LinkedList;

/**
 * Created by weimengshu on 2018/9/22.
 */
public class BinaryTreeTraversal {

    /**
     * 构建二叉树
     * @param inputList   输入序列
     */
    public static TreeNode createBinaryTree(LinkedList<Integer> inputList){
        TreeNode node = null;
        if(inputList==null || inputList.isEmpty()){
            return null;
        }
        Integer data = inputList.removeFirst();
        //这里的判空很关键。如果元素是空，说明该节点不存在，跳出这一层递归；如果元素非空，继续递归构建该节点的左右孩子。
        if(data != null){
            node = new TreeNode(data);
            node.leftChild = createBinaryTree(inputList);
            node.rightChild = createBinaryTree(inputList);
        }
        return node;
    }

    /**
     * 二叉树前序遍历
     * @param node   二叉树节点
     */
    public static void preOrderTraversal(TreeNode node){
        if(node == null){
            return;
        }
        System.out.println(node.data);
        preOrderTraversal(node.leftChild);
        preOrderTraversal(node.rightChild);
    }

    /**
     * 二叉树中序遍历
     * @param node   二叉树节点
     */
    public static void inOrderTraversal(TreeNode node){
        if(node == null){
            return;
        }
        inOrderTraversal(node.leftChild);
        System.out.println(node.data);
        inOrderTraversal(node.rightChild);
    }


    /**
     * 二叉树后序遍历
     * @param node   二叉树节点
     */
    public static void postOrderTraversal(TreeNode node){
        if(node == null){
            return;
        }
        postOrderTraversal(node.leftChild);
        postOrderTraversal(node.rightChild);
        System.out.println(node.data);
    }

    /**
     * 二叉树节点
     */
    private static class TreeNode {
        int data;
        TreeNode leftChild;
        TreeNode rightChild;

        TreeNode(int data) {
            this.data = data;
        }
    }

    public static void main(String[] args) {
        LinkedList<Integer> inputList = new LinkedList<Integer>(Arrays.asList(new Integer[]{3,2,9,null,null,10,null,null,8,null,4,}));
        TreeNode treeNode = createBinaryTree(inputList);
        System.out.println("前序遍历：");
        preOrderTraversal(treeNode);
        System.out.println("中序遍历：");
        inOrderTraversal(treeNode);
        System.out.println("后序遍历：");
        postOrderTraversal(treeNode);
    }

}


================================================
FILE: src/chapter3/part2/BinaryTreeTraversalLevel.java
================================================
package chapter3.part2;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;

/**
 * Created by weimengshu on 2018/9/22.
 */
public class BinaryTreeTraversalLevel {

    /**
     * 构建二叉树
     * @param inputList   输入序列
     */
    public static TreeNode createBinaryTree(LinkedList<Integer> inputList){
        TreeNode node = null;
        if(inputList==null || inputList.isEmpty()){
            return null;
        }
        Integer data = inputList.removeFirst();
        //这里的判空很关键。如果元素是空，说明该节点不存在，跳出这一层递归；如果元素非空，继续递归构建该节点的左右孩子。
        if(data != null){
            node = new TreeNode(data);
            node.leftChild = createBinaryTree(inputList);
            node.rightChild = createBinaryTree(inputList);
        }
        return node;
    }

    /**
     * 二叉树层序遍历
     * @param root   二叉树根节点
     */
    public static void levelOrderTraversal(TreeNode root){
        Queue<TreeNode> queue = new LinkedList<TreeNode>();
        queue.offer(root);
        while(!queue.isEmpty()){
            TreeNode node = queue.poll();
            System.out.println(node.data);
            if(node.leftChild != null){
                queue.offer(node.leftChild);
            }
            if(node.rightChild != null){
                queue.offer(node.rightChild);
            }
        }
    }

    /**
     * 二叉树节点
     */
    private static class TreeNode {
        int data;
        TreeNode leftChild;
        TreeNode rightChild;

        TreeNode(int data) {
            this.data = data;
        }
    }

    public static void main(String[] args) {
        LinkedList<Integer> inputList = new LinkedList<Integer>(Arrays.asList(new Integer[]{3,2,9,null,null,10,null,null,8,null,4,}));
        TreeNode treeNode = createBinaryTree(inputList);
        System.out.println("层序遍历：");
        levelOrderTraversal(treeNode);
    }

}


================================================
FILE: src/chapter3/part2/BinaryTreeTraversalStack.java
================================================
package chapter3.part2;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.Stack;

/**
 * Created by weimengshu on 2018/9/22.
 */
public class BinaryTreeTraversalStack {

    /**
     * 构建二叉树
     * @param inputList   输入序列
     */
    public static TreeNode createBinaryTree(LinkedList<Integer> inputList){
        TreeNode node = null;
        if(inputList==null || inputList.isEmpty()){
            return null;
        }
        Integer data = inputList.removeFirst();
        //这里的判空很关键。如果元素是空，说明该节点不存在，跳出这一层递归；如果元素非空，继续递归构建该节点的左右孩子。
        if(data != null){
            node = new TreeNode(data);
            node.leftChild = createBinaryTree(inputList);
            node.rightChild = createBinaryTree(inputList);
        }
        return node;
    }

    /**
     * 二叉树非递归前序遍历
     * @param root   二叉树根节点
     */
    public static void preOrderTraveralWithStack(TreeNode root){
        Stack<TreeNode> stack = new Stack<TreeNode>();
        TreeNode treeNode = root;
        while(treeNode!=null || !stack.isEmpty()){
            //迭代访问节点的左孩子，并入栈
            while (treeNode != null){
                System.out.println(treeNode.data);
                stack.push(treeNode);
                treeNode = treeNode.leftChild;
            }
            //如果节点没有左孩子，则弹出栈顶节点，访问节点右孩子
            if(!stack.isEmpty()){
                treeNode = stack.pop();
                treeNode = treeNode.rightChild;
            }
        }
    }

    /**
     * 二叉树节点
     */
    private static class TreeNode {
        int data;
        TreeNode leftChild;
        TreeNode rightChild;

        TreeNode(int data) {
            this.data = data;
        }
    }

    public static void main(String[] args) {
        LinkedList<Integer> inputList = new LinkedList<Integer>(Arrays.asList(new Integer[]{3,2,9,null,null,10,null,null,8,null,4,}));
        TreeNode treeNode = createBinaryTree(inputList);
        preOrderTraveralWithStack(treeNode);
    }

}


================================================
FILE: src/chapter3/part3/HeapOperator.java
================================================
package chapter3.part3;

/**
 * Created by weimengshu on 2018/7/13.
 */
import java.util.Arrays;

public class HeapOperator {

    /**
     * 上浮调整
     * @param array     待调整的堆
     */
    public static void upAdjust(int[] array) {
        int childIndex = array.length-1;
        int parentIndex = (childIndex-1)/2;
        // temp保存插入的叶子节点值，用于最后的赋值
        int temp = array[childIndex];
        while (childIndex > 0 && temp < array[parentIndex])
        {
            //无需真正交换，单向赋值即可
            array[childIndex] = array[parentIndex];
            childIndex = parentIndex;
            parentIndex = (parentIndex-1) / 2;
        }
        array[childIndex] = temp;
    }

    /**
     * 下沉调整
     * @param array     待调整的堆
     * @param parentIndex    要下沉的父节点
     * @param length    堆的有效大小
     */
    public static void downAdjust(int[] array, int parentIndex, int length) {
        // temp保存父节点值，用于最后的赋值
        int temp = array[parentIndex];
        int childIndex = 2 * parentIndex + 1;
        while (childIndex < length) {
            // 如果有右孩子，且右孩子小于左孩子的值，则定位到右孩子
            if (childIndex + 1 < length && array[childIndex + 1] < array[childIndex]) {
                childIndex++;
            }
            // 如果父节点小于任何一个孩子的值，直接跳出
            if (temp <= array[childIndex])
                break;
            //无需真正交换，单向赋值即可
            array[parentIndex] = array[childIndex];
            parentIndex = childIndex;
            childIndex = 2 * childIndex + 1;
        }
        array[parentIndex] = temp;
    }

    /**
     * 构建堆
     * @param array     待调整的堆
     */
    public static void buildHeap(int[] array) {
        // 从最后一个非叶子节点开始，依次下沉调整
        for (int i = (array.length-2)/2; i >= 0; i--) {
            downAdjust(array, i, array.length);
        }
    }

    public static void main(String[] args) {
        int[] array = new int[] {1,3,2,6,5,7,8,9,10,0};
        upAdjust(array);
        System.out.println(Arrays.toString(array));

        array = new int[] {7,1,3,10,5,2,8,9,6};
        buildHeap(array);
        System.out.println(Arrays.toString(array));
    }
}


================================================
FILE: src/chapter3/part4/PriorityQueue.java
================================================
package chapter3.part4;

/**
 * Created by weimengshu on 2018/7/13.
 */
import java.util.Arrays;

public class PriorityQueue {

    private int[] array;
    private int size;

    public PriorityQueue(){
        //队列初始长度32
        array = new int[32];
    }

    /**
     * 入队
     * @param key  入队元素
     */
    public void enQueue(int key) {
        //队列长度超出范围，扩容
        if(size >= array.length){
            resize();
        }
        array[size++] = key;
        upAdjust();
    }

    /**
     * 出队
     */
    public int deQueue() throws Exception {
        if(size <= 0){
            throw new Exception("the queue is empty !");
        }
        //获取堆顶元素
        int head = array[0];
        //最后一个元素移动到堆顶
        array[0] = array[--size];
        downAdjust();
        return head;
    }

    /**
     * 上浮调整
     */
    private void upAdjust() {
        int childIndex = size-1;
        int parentIndex = (childIndex-1)/2;
        // temp保存插入的叶子节点值，用于最后的赋值
        int temp = array[childIndex];
        while (childIndex > 0 && temp > array[parentIndex])
        {
            //无需真正交换，单向赋值即可
            array[childIndex] = array[parentIndex];
            childIndex = parentIndex;
            parentIndex = (parentIndex-1) / 2;
        }
        array[childIndex] = temp;
    }

    /**
     * 下沉调整
     */
    private void downAdjust() {
        // temp保存父节点值，用于最后的赋值
        int parentIndex = 0;
        int temp = array[parentIndex];
        int childIndex = 1;
        while (childIndex < size) {
            // 如果有右孩子，且右孩子大于左孩子的值，则定位到右孩子
            if (childIndex + 1 < size && array[childIndex + 1] > array[childIndex]) {
                childIndex++;
            }
            // 如果父节点大于任何一个孩子的值，直接跳出
            if (temp >= array[childIndex])
                break;
            //无需真正交换，单向赋值即可
            array[parentIndex] = array[childIndex];
            parentIndex = childIndex;
            childIndex = 2 * childIndex + 1;
        }
        array[parentIndex] = temp;
    }

    /**
     * 队列扩容
     */
    private void resize() {
        //队列容量翻倍
        int newSize = this.size * 2;
        this.array = Arrays.copyOf(this.array, newSize);
    }

    public static void main(String[] args) throws Exception {
        PriorityQueue priorityQueue = new PriorityQueue();
        priorityQueue.enQueue(3);
        priorityQueue.enQueue(5);
        priorityQueue.enQueue(10);
        priorityQueue.enQueue(2);
        priorityQueue.enQueue(7);
        System.out.println("出队元素：" + priorityQueue.deQueue());
        System.out.println("出队元素：" + priorityQueue.deQueue());
    }
}


================================================
FILE: src/chapter4/part2/BubbleSort.java
================================================
package chapter4.part2;

import java.util.Arrays;

public class BubbleSort {

    public static void sort(int array[])
    {
        int tmp  = 0;
        //记录最后一次交换的位置
        int lastExchangeIndex = 0;
        //无序数列的边界，每次比较只需要比到这里为止
        int sortBorder = array.length - 1;
        for(int i = 0; i < array.length; i++)
        {
            //有序标记，每一轮的初始是true
            boolean isSorted = true;

            for(int j = 0; j < sortBorder; j++)
            {
                if(array[j] > array[j+1])
                {
                    tmp = array[j];
                    array[j] = array[j+1];
                    array[j+1] = tmp;
                    //有元素交换，所以不是有序，标记变为false
                    isSorted = false;
                    //把无序数列的边界更新为最后一次交换元素的位置
                    lastExchangeIndex = j;
                }
            }
            sortBorder = lastExchangeIndex;
            if(isSorted){
                break;
            }
        }
    }

    public static void main(String[] args){
        int[] array = new int[]{3,4,2,1,5,6,7,8};
        sort(array);
        System.out.println(Arrays.toString(array));
    }
}


================================================
FILE: src/chapter4/part2/CockTailSort.java
================================================
package chapter4.part2;

import java.util.Arrays;

public class CockTailSort {

    public static void sort(int array[])
    {
        int tmp  = 0;
        for(int i=0; i<array.length/2; i++)
        {
            //有序标记，每一轮的初始是true
            boolean isSorted = true;
            //奇数轮，从左向右比较和交换
            for(int j=i; j<array.length-i-1; j++)
            {
                if(array[j] > array[j+1])
                {
                    tmp = array[j];
                    array[j] = array[j+1];
                    array[j+1] = tmp;
                    //有元素交换，所以不是有序，标记变为false
                    isSorted = false;
                }
            }
            if(isSorted){
                break;
            }

            //偶数轮之前，重新标记为true
            isSorted = true;
            //偶数轮，从右向左比较和交换
            for(int j=array.length-i-1; j>i; j--)
            {
                if(array[j] < array[j-1])
                {
                    tmp = array[j];
                    array[j] = array[j-1];
                    array[j-1] = tmp;
                    //有元素交换，所以不是有序，标记变为false
                    isSorted = false;
                }
            }
            if(isSorted){
                break;
            }
        }
    }

    public static void main(String[] args){
        int[] array = new int[]{2,3,4,5,6,7,8,1};
        sort(array);
        System.out.println(Arrays.toString(array));
    }
}


================================================
FILE: src/chapter4/part3/QuickSort.java
================================================
package chapter4.part3;

/**
 * Created by weimengshu on 2018/7/13.
 */
import java.util.Arrays;

public class QuickSort {

    public static void quickSort(int[] arr, int startIndex, int endIndex) {
        // 递归结束条件：startIndex大等于endIndex的时候
        if (startIndex >= endIndex) {
            return;
        }
        // 得到基准元素位置
        int pivotIndex = partition(arr, startIndex, endIndex);
        // 根据基准元素，分成两部分递归排序
        quickSort(arr, startIndex, pivotIndex - 1);
        quickSort(arr, pivotIndex + 1, endIndex);
    }

    /**
     * 分治（双边循环法）
     * @param arr     待交换的数组
     * @param startIndex    起始下标
     * @param endIndex    结束下标
     */
    private static int partition(int[] arr, int startIndex, int endIndex) {
        // 取第一个位置的元素作为基准元素（也可以选择随机位置）
        int pivot = arr[startIndex];
        int left = startIndex;
        int right = endIndex;

        while( left != right) {
            //控制right指针比较并左移
            while(left<right && arr[right] > pivot){
                right--;
            }
            //控制left指针比较并右移
            while( left<right && arr[left] <= pivot) {
                left++;
            }
            //交换left和right指向的元素
            if(left<right) {
                int p = arr[left];
                arr[left] = arr[right];
                arr[right] = p;
            }
        }

        //pivot和指针重合点交换
        arr[startIndex] = arr[left];
        arr[left] = pivot;

        return left;
    }

    /**
     * 分治（单边循环法）
     * @param arr     待交换的数组
     * @param startIndex    起始下标
     * @param endIndex    结束下标
     */
    private static int partitionV2(int[] arr, int startIndex, int endIndex) {
        // 取第一个位置的元素作为基准元素（也可以选择随机位置）
        int pivot = arr[startIndex];
        int mark = startIndex;

        for(int i=startIndex+1; i<=endIndex; i++){
            if(arr[i]<pivot){
                mark ++;
                int p = arr[mark];
                arr[mark] = arr[i];
                arr[i] = p;
            }
        }

        arr[startIndex] = arr[mark];
        arr[mark] = pivot;
        return mark;
    }

    public static void main(String[] args) {
        int[] arr = new int[] {4,4,6,5,3,2,8,1};
        quickSort(arr, 0, arr.length-1);
        System.out.println(Arrays.toString(arr));
    }
}


================================================
FILE: src/chapter4/part3/QuickSortWithStack.java
================================================
package chapter4.part3;

/**
 * Created by weimengshu on 2018/7/13.
 */
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Stack;

public class QuickSortWithStack {

    public static void quickSort(int[] arr, int startIndex, int endIndex) {
        // 用一个集合栈来代替递归的函数栈
        Stack<Map<String, Integer>> quickSortStack = new Stack<Map<String, Integer>>();
        // 整个数列的起止下标，以哈希的形式入栈
        Map rootParam = new HashMap();
        rootParam.put("startIndex", startIndex);
        rootParam.put("endIndex", endIndex);
        quickSortStack.push(rootParam);

        // 循环结束条件：栈为空时结束
        while (!quickSortStack.isEmpty()) {
            // 栈顶元素出栈，得到起止下标
            Map<String, Integer> param = quickSortStack.pop();
            // 得到基准元素位置
            int pivotIndex = partition(arr, param.get("startIndex"), param.get("endIndex"));
            // 根据基准元素分成两部分, 把每一部分的起止下标入栈
            if(param.get("startIndex") <  pivotIndex -1){
                Map<String, Integer> leftParam = new HashMap<String, Integer>();
                leftParam.put("startIndex",  param.get("startIndex"));
                leftParam.put("endIndex", pivotIndex -1);
                quickSortStack.push(leftParam);
            }
            if(pivotIndex + 1 < param.get("endIndex")){
                Map<String, Integer> rightParam = new HashMap<String, Integer>();
                rightParam.put("startIndex", pivotIndex + 1);
                rightParam.put("endIndex", param.get("endIndex"));
                quickSortStack.push(rightParam);
            }
        }
    }

    /**
     * 分治（单边循环法）
     * @param arr     待交换的数组
     * @param startIndex    起始下标
     * @param endIndex    结束下标
     */
    private static int partition(int[] arr, int startIndex, int endIndex) {
        // 取第一个位置的元素作为基准元素（也可以选择随机位置）
        int pivot = arr[startIndex];
        int mark = startIndex;

        for(int i=startIndex+1; i<=endIndex; i++){
            if(arr[i]<pivot){
                mark ++;
                int p = arr[mark];
                arr[mark] = arr[i];
                arr[i] = p;
            }
        }

        arr[startIndex] = arr[mark];
        arr[mark] = pivot;
        return mark;
    }

    public static void main(String[] args) {
        int[] arr = new int[] {4,7,6,5,3,2,8,1};
        quickSort(arr, 0, arr.length-1);
        System.out.println(Arrays.toString(arr));
    }

}


================================================
FILE: src/chapter4/part4/HeapSort.java
================================================
package chapter4.part4;

/**
 * Created by weimengshu on 2018/7/13.
 */
import java.util.Arrays;

public class HeapSort {

    /**
     * 下沉调整
     * @param array     待调整的堆
     * @param parentIndex    要下沉的父节点
     * @param length    堆的有效大小
     */
    public static void downAdjust(int[] array, int parentIndex, int length) {
        // temp保存父节点值，用于最后的赋值
        int temp = array[parentIndex];
        int childIndex = 2 * parentIndex + 1;
        while (childIndex < length) {
            // 如果有右孩子，且右孩子大于左孩子的值，则定位到右孩子
            if (childIndex + 1 < length && array[childIndex + 1] > array[childIndex]) {
                childIndex++;
            }
            // 如果父节点大于等于任何一个孩子的值，直接跳出
            if (temp >= array[childIndex])
                break;
            //无需真正交换，单向赋值即可
            array[parentIndex] = array[childIndex];
            parentIndex = childIndex;
            childIndex = 2 * childIndex + 1;
        }
        array[parentIndex] = temp;
    }

    /**
     * 堆排序(升序)
     * @param array     待调整的堆
     */
    public static void heapSort(int[] array) {
        // 1.把无序数组构建成最大堆。
        for (int i = (array.length-2)/2; i >= 0; i--) {
            downAdjust(array, i, array.length);
        }
        System.out.println(Arrays.toString(array));
        // 2.循环交换集合尾部元素到堆顶，并调节堆产生新的堆顶。
        for (int i = array.length - 1; i > 0; i--) {
            // 最后一个元素和第一元素进行交换
            int temp = array[i];
            array[i] = array[0];
            array[0] = temp;
            // 下沉调整最大堆
            downAdjust(array, 0, i);
        }
    }

    public static void main(String[] args) {
        int[] arr = new int[] {1,3,2,6,5,7,8,9,10,0};
        heapSort(arr);
        System.out.println(Arrays.toString(arr));
    }
}


================================================
FILE: src/chapter4/part5/BucketSort.java
================================================
package chapter4.part5;

/**
 * Created by weimengshu on 2018/7/13.
 */
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedList;

public class BucketSort {

    public static double[] bucketSort(double[] array){

        //1.得到数列的最大值和最小值，并算出差值d
        double max = array[0];
        double min = array[0];
        for(int i=1; i<array.length; i++) {
            if(array[i] > max) {
                max = array[i];
            }
            if(array[i] < min) {
                min = array[i];
            }
        }
        double d = max - min;

        //2.初始化桶
        int bucketNum = array.length;
        ArrayList<LinkedList<Double>> bucketList = new ArrayList<LinkedList<Double>>(bucketNum);
        for(int i = 0; i < bucketNum; i++){
            bucketList.add(new LinkedList<Double>());
        }

        //3.遍历原始数组，将每个元素放入桶中
        for(int i = 0; i < array.length; i++){
            int num = (int)((array[i] - min)  * (bucketNum-1) / d);
            bucketList.get(num).add(array[i]);
        }

        //4.对每个桶内部进行排序
        for(int i = 0; i < bucketList.size(); i++){
            //JDK底层采用了归并排序或归并的优化版本
            Collections.sort(bucketList.get(i));
        }

        //5.输出全部元素
        double[] sortedArray = new double[array.length];
        int index = 0;
        for(LinkedList<Double> list : bucketList){
            for(double element : list){
                sortedArray[index] = element;
                index++;
            }
        }
        return sortedArray;
    }

    public static void main(String[] args) {
        double[] array = new double[] {4.12,6.421,0.0023,3.0,2.123,8.122,4.12, 10.09};
        double[] sortedArray = bucketSort(array);
        System.out.println(Arrays.toString(sortedArray));
    }
}


================================================
FILE: src/chapter4/part5/CountSort.java
================================================
package chapter4.part5;

/**
 * Created by weimengshu on 2018/7/13.
 */
import java.util.Arrays;

public class CountSort {

    public static int[] countSort(int[] array) {
        //1.得到数列的最大值
        int max = array[0];
        for(int i=1; i<array.length; i++){
            if(array[i] > max){
                max = array[i];
            }
        }
        //2.根据数列最大值确定统计数组的长度
        int[] countArray = new int[max+1];
        //3.遍历数列，填充统计数组
        for(int i=0; i<array.length; i++){
            countArray[array[i]]++;
        }
        //4.遍历统计数组，输出结果
        int index = 0;
        int[] sortedArray = new int[array.length];
        for(int i=0; i<countArray.length; i++){
            for(int j=0; j<countArray[i]; j++){
                sortedArray[index++] = i;
            }
        }
        return sortedArray;
    }

    public static int[] countSortV2(int[] array) {
        //1.得到数列的最大值和最小值，并算出差值d
        int max = array[0];
        int min = array[0];
        for(int i=1; i<array.length; i++) {
            if(array[i] > max) {
                max = array[i];
            }
            if(array[i] < min) {
                min = array[i];
            }
        }
        int d = max - min;
        //2.创建统计数组并统计对应元素个数
        int[] countArray = new int[d+1];
        for(int i=0; i<array.length; i++) {
            countArray[array[i]-min]++;
        }
        //3.统计数组做变形，后面的元素等于前面的元素之和
        for(int i=1;i<countArray.length;i++) {
            countArray[i] += countArray[i-1];
        }
        //4.倒序遍历原始数列，从统计数组找到正确位置，输出到结果数组
        int[] sortedArray = new int[array.length];
        for(int i=array.length-1;i>=0;i--) {
            sortedArray[countArray[array[i]-min]-1]=array[i];
            countArray[array[i]-min]--;
        }
        return sortedArray;
    }

    public static void main(String[] args) {
        int[] array = new int[] {4,4,6,5,3,2,8,1,7,5,6,0,10};
        int[] sortedArray = countSort(array);
        System.out.println(Arrays.toString(sortedArray));

        array = new int[] {95,94,91,98,99,90,99,93,91,92};
        sortedArray = countSort(array);
        System.out.println(Arrays.toString(sortedArray));
    }
}


================================================
FILE: src/chapter5/part10/BigNumberSum.java
================================================
package chapter5.part10;

/**
 * Created by weimengshu on 2018/10/20.
 */
public class BigNumberSum {

    /**
     * 大整数求和
     * @param bigNumberA  大整数A
     * @param bigNumberB  大整数B
     */
    public static String bigNumberSum(String bigNumberA, String bigNumberB) {
        //1.把两个大整数用数组逆序存储，数组长度等于较大整数位数+1
        int maxLength = bigNumberA.length() > bigNumberB.length() ? bigNumberA.length() : bigNumberB.length();
        int[] arrayA = new int[maxLength+1];
        for(int i=0; i< bigNumberA.length(); i++){
            arrayA[i] = bigNumberA.charAt(bigNumberA.length()-1-i) - '0';
        }
        int[] arrayB = new int[maxLength+1];
        for(int i=0; i< bigNumberB.length(); i++){
            arrayB[i] = bigNumberB.charAt(bigNumberB.length()-1-i) - '0';
        }
        //2.构建result数组，数组长度等于较大整数位数+1
        int[] result = new int[maxLength+1];
        //3.遍历数组，按位相加
        for(int i=0; i<result.length; i++){
            int temp = result[i];
            temp += arrayA[i];
            temp += arrayB[i];
            //判断是否进位
            if(temp >= 10){
                temp = temp-10;
                result[i+1] = 1;
            }
            result[i] = temp;
        }
        //4.把result数组再次逆序并转成String
        StringBuilder sb = new StringBuilder();
        //是否找到大整数的最高有效位
        boolean findFirst = false;
        for (int i = result.length - 1; i >= 0; i--) {
            if(!findFirst){
                if(result[i] == 0){
                    continue;
                }
                findFirst = true;
            }
            sb.append(result[i]);
        }
        return sb.toString();
    }

    public static void main(String[] args) {
        System.out.println(bigNumberSum("426709752318", "95481253129"));
    }
}


================================================
FILE: src/chapter5/part11/GoldMining.java
================================================
package chapter5.part11;

/**
 * Created by weimengshu on 2018/10/26.
 */
public class GoldMining {

    /**
     * 获得金矿最优收益
     * @param w  工人数量
     * @param p  金矿开采所需工人数量
     * @param g  金矿储量
     */
    public static int getBestGoldMiningV3(int w, int[] p, int[] g){
        //创建当前结果
        int[] results = new int[w+1];
        //填充一维数组
        for(int i=1; i<=g.length; i++){
            for(int j=w; j>=1; j--){
               if(j>=p[i-1]){
                    results[j] = Math.max(results[j],  results[j-p[i-1]]+ g[i-1]);
                }
            }
        }
        //返回最后一个格子的值
        return results[w];
    }

    /**
     * 获得金矿最优收益
     * @param w  工人数量
     * @param p  金矿开采所需工人数量
     * @param g  金矿储量
     */
    public static int getBestGoldMiningV2(int w, int[] p, int[] g){
        //创建表格
        int[][] resultTable = new int[g.length+1][w+1];
        //填充表格
        for(int i=1; i<=g.length; i++){
            for(int j=1; j<=w; j++){
                if(j<p[i-1]){
                    resultTable[i][j] = resultTable[i-1][j];
                }else{
                    resultTable[i][j] = Math.max(resultTable[i-1][j],  resultTable[i-1][j-p[i-1]]+ g[i-1]);
                }
            }
        }
        //返回最后一个格子的值
        return resultTable[g.length][w];
    }

    /**
     * 获得金矿最优收益
     * @param w  工人数量
     * @param n  可选金矿数量
     * @param p  金矿开采所需工人数量
     * @param g  金矿储量
     */
    public static int getBestGoldMining(int w, int n, int[] p, int[] g){
        if(w==0 || n==0){
            return 0;
        }
        if(w<p[n-1]){
            return getBestGoldMining(w, n-1, p, g);
        }
        return Math.max(getBestGoldMining(w, n-1, p, g), getBestGoldMining(w-p[n-1], n-1, p, g)+g[n-1]);
    }


    public static void main(String[] args) {
        int w = 10;
        int[] p = {5, 5, 3, 4 ,3};
        int[] g = {400, 500, 200, 300 ,350};
        System.out.println("最优收益：" + getBestGoldMining(w, g.length, p, g));
    }

}


================================================
FILE: src/chapter5/part12/FindLostNum.java
================================================
package chapter5.part12;

/**
 * Created by weimengshu on 2018/10/10.
 */
public class FindLostNum {

    public static int[] findLostNum(int[] array) {
        //用于存储两个出现奇数次的整数
        int result[] = new int[2];
        //第一次整体异或
        int xorResult = 0;
        for(int i=0;i<array.length;i++){
            xorResult^=array[i];
        }
        //如果异或结果为0，说明输入数组不符合题目
        if(xorResult == 0){
            return null;
        }
        //确定两个整数的不同位，以此来做分组
        int separator = 1;
        while (0==(xorResult&separator)){
            separator<<=1;
        }
        //第二次分组异或
        for(int i=0;i<array.length;i++){
            if(0==(array[i]&separator)){
                result[0]^=array[i];
            }else {
                result[1]^=array[i];
            }
        }

        return result;
    }

    public static void main(String[] args) {
        int[] array = {4,1,2,2,5,1,4,3};
        int[] result = findLostNum(array);
        System.out.println(result[0] + "," + result[1]);
    }
}


================================================
FILE: src/chapter5/part2/LinkedListCycle.java
================================================
package chapter5.part2;

/**
 * Created by weimengshu on 2018/8/24.
 */
public class LinkedListCycle {

    /**
     * 判断是否有环
     * @param head  链表头节点
     */
    public static boolean isCycle(Node head) {
        Node p1 = head;
        Node p2 = head;
        while (p2!=null && p2.next!=null){
            p1 = p1.next;
            p2 = p2.next.next;
            if(p1 == p2){
                return true;
            }
        }
        return false;
    }

    /**
     * 链表节点
     */
    private static class Node {
        int data;
        Node next;
        Node(int data) {
            this.data = data;
        }
    }

    public static void main(String[] args) throws Exception {
        Node node1 = new Node(5);
        Node node2 = new Node(3);
        Node node3 = new Node(7);
        Node node4 = new Node(2);
        Node node5 = new Node(6);
        node1.next = node2;
        node2.next = node3;
        node3.next = node4;
        node4.next = node5;
        node5.next = node2;

        System.out.println(isCycle(node1));
    }
}


================================================
FILE: src/chapter5/part3/MinStack.java
================================================
package chapter5.part3;

import java.util.Stack;

/**
 * Created by weimengshu on 2018/8/24.
 */
public class MinStack {

    private Stack<Integer> mainStack = new Stack<Integer>();
    private Stack<Integer> minStack = new Stack<Integer>();

    /**
     * 入栈操作
     * @param element  入栈的元素
     */
    public void push(int element) {
        mainStack.push(element);
        //如果辅助栈为空，或新元素小于等于辅助栈栈顶，则新元素压入辅助栈
        if (minStack.empty() || element  <= minStack.peek()) {
            minStack.push(element);
        }
    }

    /**
     * 出栈操作
     */
    public Integer pop() {
        //如果出栈元素和辅助栈栈顶元素值相等，辅助栈出栈
        if (mainStack.peek().equals(minStack.peek())) {
            minStack.pop();
        }
        return mainStack.pop();
    }

    /**
     * 获取栈的最小元素
     */
    public int getMin() throws Exception {
        if (mainStack.empty()) {
            throw new Exception("stack is empty");
        }

        return minStack.peek();
    }

    public static void main(String[] args) throws Exception {
        MinStack stack = new MinStack();
        stack.push(4);
        stack.push(9);
        stack.push(7);
        stack.push(3);
        stack.push(8);
        stack.push(5);
        System.out.println(stack.getMin());
        stack.pop();
        stack.pop();
        stack.pop();
        System.out.println(stack.getMin());
    }
}


================================================
FILE: src/chapter5/part4/GreatestCommonDivisor.java
================================================
package chapter5.part4;

/**
 * Created by weimengshu on 2018/10/6.
 */
public class GreatestCommonDivisor {

    public static int getGreatestCommonDivisor(int a, int b){
        int big = a>b ? a:b;
        int small = a<b ? a:b;
        if(big%small == 0){
            return small;
        }
        for(int i= small/2; i>1; i--){
            if(small%i==0 && big%i==0){
                return i;
            }
        }
        return  1;
    }

    public static int getGreatestCommonDivisorV2(int a, int b){
        int big = a>b ? a:b;
        int small = a<b ? a:b;
        if(big%small == 0){
            return small;
        }
        return getGreatestCommonDivisorV2(big%small, small);
    }

    public static int getGreatestCommonDivisorV3(int a, int b){
        if(a == b){
            return a;
        }
        int big = a>b ? a:b;
        int small = a<b ? a:b;
        return getGreatestCommonDivisorV3(big - small, small);
    }

    public static int gcd(int a, int b){
        if(a == b){
            return a;
        }
        if((a&1)==0 && (b&1)==0){
            return gcd(a >> 1, b >> 1)<<1;
        } else if((a&1)==0 && (b&1)!=0){
            return gcd(a >> 1, b);
        } else if((a&1)!=0 && (b&1)==0){
            return gcd(a, b >> 1);
        } else {
            int big = a>b ? a:b;
            int small = a<b ? a:b;
            return gcd(big - small, small);
        }
    }

    public static void main(String[] args) {
        System.out.println(gcd(25, 5));
        System.out.println(gcd(100, 80));
        System.out.println(gcd(27, 14));
    }
}


================================================
FILE: src/chapter5/part5/PowerOf2.java
================================================
package chapter5.part5;

/**
 * Created by weimengshu on 2018/10/10.
 */
public class PowerOf2 {

    public static boolean isPowerOf2(int num) {
        int temp = 1;
        while(temp<=num){
            if(temp == num){
                return true;
            }
            temp = temp*2;
        }
        return false;
    }

    public static boolean isPowerOf2V2(int num) {
        int temp = 1;
        while(temp<=num){
            if(temp == num){
                return true;
            }
            temp = temp<<1;
        }
        return false;
    }

    public static boolean isPowerOf2V3(int num) {
        return (num&num-1) == 0;
    }

    public static void main(String[] args) {
        System.out.println(isPowerOf2V3(32));
        System.out.println(isPowerOf2V3(19));
    }
}


================================================
FILE: src/chapter5/part6/MaxSortedDistance.java
================================================
package chapter5.part6;

/**
 * Created by weimengshu on 2018/7/13.
 */

public class MaxSortedDistance {

    public static int getMaxSortedDistance(int[] array){

        //1.得到数列的最大值和最小值
        int max = array[0];
        int min = array[0];
        for(int i=1; i<array.length; i++) {
            if(array[i] > max) {
                max = array[i];
            }
            if(array[i] < min) {
                min = array[i];
            }
        }
        int d = max - min;
        //如果max和min相等，说明数组所有元素都相等，返回0
        if(d == 0){
            return 0;
        }

        //2.初始化桶
        int bucketNum = array.length;
        Bucket[] buckets = new Bucket[bucketNum];
        for(int i = 0; i < bucketNum; i++){
            buckets[i] = new Bucket();
        }

        //3.遍历原始数组，确定每个桶的最大最小值
        for(int i = 0; i < array.length; i++){
            //确定数组元素所归属的桶下标
            int index = ((array[i] - min)  * (bucketNum-1) / d);
            if(buckets[index].min==null || buckets[index].min>array[i]){
                buckets[index].min = array[i];
            }
            if(buckets[index].max==null || buckets[index].max<array[i]){
                buckets[index].max = array[i];
            }
        }

        //4.遍历桶，找到最大差值
        int leftMax = buckets[0].max;
        int maxDistance = 0;
        for (int i=1; i<buckets.length; i++) {
            if (buckets[i].min == null) {
                continue;
            }
            if (buckets[i].min - leftMax > maxDistance) {
                maxDistance = buckets[i].min - leftMax;
            }
            leftMax = buckets[i].max;
        }

        return maxDistance;
    }

    /**
     * 桶
     */
    private static class Bucket {
        Integer min;
        Integer max;
    }

    public static void main(String[] args) {
        int[] array = new int[] {2,6,3,4,5,10,9};
        System.out.println(getMaxSortedDistance(array));
    }
}


================================================
FILE: src/chapter5/part7/StackQueue.java
================================================
package chapter5.part7;

import java.util.Stack;

/**
 * Created by weimengshu on 2018/8/24.
 */
public class StackQueue {

    private Stack<Integer> stackA = new Stack<Integer>();
    private Stack<Integer> stackB = new Stack<Integer>();

    /**
     * 入队操作
     * @param element  入队的元素
     */
    public void enQueue(int element) {
        stackA.push(element);
    }

    /**
     * 出队操作
     */
    public Integer deQueue() {
        if(stackB.isEmpty()){
            if(stackA.isEmpty()){
                return null;
            }
            transfer();
        }
        return stackB.pop();
    }

    /**
     * 栈A元素转移到栈B
     */
    private void transfer(){
        while (!stackA.isEmpty()){
            stackB.push(stackA.pop());
        }
    }

    public static void main(String[] args) throws Exception {
        StackQueue stackQueue = new StackQueue();
        stackQueue.enQueue(1);
        stackQueue.enQueue(2);
        stackQueue.enQueue(3);
        System.out.println(stackQueue.deQueue());
        System.out.println(stackQueue.deQueue());
        stackQueue.enQueue(4);
        System.out.println(stackQueue.deQueue());
        System.out.println(stackQueue.deQueue());
    }
}


================================================
FILE: src/chapter5/part8/FindNearestNumber.java
================================================
package chapter5.part8;

import java.util.Arrays;

/**
 * Created by weimengshu on 2017/8/10.
 */
public class FindNearestNumber {

    public static int[] findNearestNumber(int[] numbers){
        //1.从后向前查看逆序区域，找到逆序区域的前一位，也就是数字置换的边界
        int index = findTransferPoint(numbers);
        //如果数字置换边界是0，说明整个数组已经逆序，无法得到更大的相同数字组成的整数，返回null
        if(index == 0){
            return null;
        }
        //2.把逆序区域的前一位和逆序区域中刚刚大于它的数字交换位置
        //拷贝入参，避免直接修改入参
        int[] numbersCopy = Arrays.copyOf(numbers, numbers.length);
        exchangeHead(numbersCopy, index);
        //3.把原来的逆序区域转为顺序
        reverse(numbersCopy, index);
        return numbersCopy;
    }

    private static int findTransferPoint(int[] numbers){
        for(int i=numbers.length-1; i>0; i--){
            if(numbers[i] > numbers[i-1]){
                return i;
            }
        }
        return 0;
    }

    private static int[] exchangeHead(int[] numbers, int index){
        int head = numbers[index-1];
        for(int i=numbers.length-1; i>0; i--){
            if(head < numbers[i]){
                numbers[index-1] =  numbers[i];
                numbers[i] = head;
                break;
            }
        }
        return numbers;
    }

    private static int[] reverse(int[] num, int index){
        for(int i=index,j=num.length-1; i<j; i++,j--){
            int temp = num[i];
            num[i] = num[j];
            num[j] = temp;
        }
        return num;
    }

    public static void main(String[] args) {
        int[] numbers = {1,2,3,4,5};
        //打印12345之后的10个全排列整数
        for(int i=0; i<10;i++){
            numbers = findNearestNumber(numbers);
            outputNumbers(numbers);
        }
    }

    //输出数组
    private static void outputNumbers(int[] numbers){
        for(int i : numbers){
            System.out.print(i);
        }
        System.out.println();
    }
}


================================================
FILE: src/chapter5/part9/RemoveKDigits.java
================================================
package chapter5.part9;

/**
 * Created by weimengshu on 2018/10/20.
 */
public class RemoveKDigits {

    /**
     * 删除整数的k个数字，获得删除后的最小值
     * @param num  原整数
     * @param k  删除数量
     */
    public static String removeKDigits(String num, int k) {
        for(int i=0; i<k; i++){
            boolean hasCut = false;
            //从左向右遍历，找到比自己右侧数字大的数字并删除
            for(int j=0; j<num.length()-1;j++){
                if(num.charAt(j) > num.charAt(j+1)){
                    num = num.substring(0, j) + num.substring(j+1,num.length());
                    hasCut = true;
                    break;
                }
            }
            //如果没有找到要删除的数字，则删除最后一个数字
            if(!hasCut){
                num = num.substring(0, num.length()-1);
            }
        }
        //清除整数左侧的数字0
        int start = 0;
        for(int j=0; j<num.length()-1; j++){
            if(num.charAt(j) != '0'){
                break;
            }
            start++;
        }
        num = num.substring(start, num.length()) ;
        //如果整数的所有数字都被删除了，直接返回0
        if(num.length() == 0){
            return "0";
        }
        return num;
    }

    /**
     * 删除整数的k个数字，获得删除后的最小值
     * @param num  原整数
     * @param k  删除数量
     */
    public static String removeKDigitsV2(String num, int k) {
        //新整数的最终长度 = 原整数长度 - k
        int newLength = num.length() - k;
        //创建一个栈，用于接收所有的数字
        char[] stack = new char[num.length()];
        int top = 0;
        for (int i = 0; i < num.length(); ++i) {
            //遍历当前数字
            char c = num.charAt(i);
            //当栈顶数字大于遍历到的当前数字，栈顶数字出栈（相当于删除数字）
            while (top > 0 && stack[top-1] > c && k > 0) {
                top -= 1;
                k -= 1;
            }
            //如果遇到数字0，且栈为空，0不入栈
            if('0' == c && top == 0){
                newLength--;
                if(newLength <= 0){
                    return "0";
                }
                continue;
            }
            //遍历到的当前数字入栈
            stack[top++] = c;
        }
        // 用栈构建新的整数字符串
        return newLength<=0 ? "0" : new String(stack, 0, newLength);
    }

    public static void main(String[] args) {
        System.out.println(removeKDigits("1593212", 3));
        System.out.println(removeKDigits("30200", 1));
        System.out.println(removeKDigits("10", 2));
        System.out.println(removeKDigits("541270936", 3));
        System.out.println(removeKDigits("1593212", 4));
        System.out.println(removeKDigits("1000020000000010", 2));
    }
}


================================================
FILE: src/chapter6/part2/MyBitmap.java
================================================
package chapter6.part2;

/**
 * Created by weimengshu on 2017/8/10.
 */
public class MyBitmap {

    //每一个word是一个long类型元素，对应64位二进制
    private long[] words;
    //bitmap的位数大小
    private int size;

    public MyBitmap(int size) {
        this.size = size;
        this.words = new long[(getWordIndex(size-1) + 1)];
    }

    /**
     * 判断bitmap某一位的状态
     * @param bitIndex  位图的第bitIndex位
     */
    public boolean getBit(int bitIndex) {
        if(bitIndex<0 || bitIndex>size-1){
            throw new IndexOutOfBoundsException("超过bitmap有效范围");
        }
        int wordIndex = getWordIndex(bitIndex);
        return (words[wordIndex] & (1L << bitIndex)) != 0;
    }

    /**
     * 把bitmap某一位设为真
     * @param bitIndex  位图的第bitIndex位
     */
    public void setBit(int bitIndex) {
        if(bitIndex<0 || bitIndex>size-1){
            throw new IndexOutOfBoundsException("超过bitmap有效范围");
        }
        int wordIndex = getWordIndex(bitIndex);
        words[wordIndex] |= (1L << bitIndex);
    }

    /**
     * 定位bitmap某一位所对应的word
     * @param bitIndex  位图的第bitIndex位
     */
    private int getWordIndex(int bitIndex) {
        //右移6位，相当于除以64
        return bitIndex >> 6;
    }

    public static void main(String[] args) {
        MyBitmap bitMap = new MyBitmap(128);
        bitMap.setBit(126);
        bitMap.setBit(75);
        System.out.println(bitMap.getBit(126));
        System.out.println(bitMap.getBit(78));
    }

}


================================================
FILE: src/chapter6/part3/LRUCache.java
================================================
package chapter6.part3;

import java.util.HashMap;


public class LRUCache {

    private Node head;
    private Node end;
    //缓存存储上限
    private int limit;

    private HashMap<String, Node> hashMap;

    public LRUCache(int limit) {
        this.limit = limit;
        hashMap = new HashMap<String, Node>();
    }

    public String get(String key) {
        Node node = hashMap.get(key);
        if (node == null){
            return null;
        }
        refreshNode(node);
        return node.value;
    }

    public void put(String key, String value) {
        Node node = hashMap.get(key);
        if (node == null) {
            //如果key不存在，插入key-value
            if (hashMap.size() >= limit) {
                String oldKey = removeNode(head);
                hashMap.remove(oldKey);
            }
            node = new Node(key, value);
            addNode(node);
            hashMap.put(key, node);
        }else {
            //如果key存在，刷新key-value
            node.value = value;
            refreshNode(node);
        }
    }

    public void remove(String key) {
        Node node = hashMap.get(key);
        if(node == null){
            return;
        }
        removeNode(node);
        hashMap.remove(key);
    }

    /**
     * 刷新被访问的节点位置
     * @param  node 被访问的节点
     */
    private void refreshNode(Node node) {
        //如果访问的是尾节点，无需移动节点
        if (node == end) {
            return;
        }
        //移除节点
        removeNode(node);
        //重新插入节点
        addNode(node);
    }

    /**
     * 删除节点
     * @param  node 要删除的节点
     */
    private String removeNode(Node node) {
        if(node == head && node == end){
            //移除唯一的节点
            head = null;
            end = null;
        }else if(node == end){
            //移除尾节点
            end = end.pre;
            end.next = null;
        }else if(node == head){
            //移除头节点
            head = head.next;
            head.pre = null;
        }else {
            //移除中间节点
            node.pre.next = node.next;
            node.next.pre = node.pre;
        }
        return node.key;
    }

    /**
     * 尾部插入节点
     * @param  node 要插入的节点
     */
    private void addNode(Node node) {
        if(end != null) {
            end.next = node;
            node.pre = end;
            node.next = null;
        }
        end = node;
        if(head == null){
            head = node;
        }
    }

    class Node {
        Node(String key, String value){
            this.key = key;
            this.value = value;
        }
        public Node pre;
        public Node next;
        public String key;
        public String value;
    }

    public static void main(String[] args) {
        LRUCache lruCache = new LRUCache(5);
        lruCache.put("001", "用户1信息");
        lruCache.put("002", "用户2信息");
        lruCache.put("003", "用户3信息");
        lruCache.put("004", "用户4信息");
        lruCache.put("005", "用户5信息");
        lruCache.get("002");
        lruCache.put("004", "用户4信息更新");
        lruCache.put("006", "用户6信息");
        System.out.println(lruCache.get("001"));
        System.out.println(lruCache.get("006"));
    }
}


================================================
FILE: src/chapter6/part4/AStar.java
================================================
package chapter6.part4;
import java.util.ArrayList;
import java.util.List;

public class AStar {

    //迷宫地图
    public static final int[][] MAZE = {
            { 0, 0, 0, 0, 0, 0, 0 },
            { 0, 0, 0, 1, 0, 0, 0 },
            { 0, 0, 0, 1, 0, 0, 0 },
            { 0, 0, 0, 1, 0, 0, 0 },
            { 0, 0, 0, 0, 0, 0, 0 }
    };

    /**
     * A星寻路主逻辑
     * @param start  迷宫起点
     * @param end  迷宫终点
     */
    public static Grid aStarSearch(Grid start, Grid end) {
        ArrayList<Grid> openList = new ArrayList<Grid>();
        ArrayList<Grid> closeList = new ArrayList<Grid>();
        //把起点加入 openList
        openList.add(start);
        //主循环，每一轮检查一个当前方格节点
        while (openList.size() > 0) {
            // 在openList中查找 F值最小的节点作为当前方格节点
            Grid currentGrid = findMinGird(openList);
            // 当前方格节点从openList中移除
            openList.remove(currentGrid);
            // 当前方格节点进入 closeList
            closeList.add(currentGrid);
            // 找到所有邻近节点
            List<Grid> neighbors = findNeighbors(currentGrid, openList, closeList);
            for (Grid grid : neighbors) {
                //邻近节点不在openList中，标记父亲、G、H、F，并放入openList
                grid.initGrid(currentGrid, end);
                openList.add(grid);
            }
            //如果终点在openList中，直接返回终点格子
            for (Grid grid : openList){
                if ((grid.x == end.x) && (grid.y == end.y)) {
                    return grid;
                }
            }
        }
        //openList用尽，仍然找不到终点，说明终点不可到达，返回空
        return null;
    }

    private static Grid findMinGird(ArrayList<Grid> openList) {
        Grid tempGrid = openList.get(0);
        for (Grid grid : openList) {
            if (grid.f < tempGrid.f) {
                tempGrid = grid;
            }
        }
        return tempGrid;
    }

    private static ArrayList<Grid> findNeighbors(Grid grid, List<Grid> openList, List<Grid> closeList) {
        ArrayList<Grid> gridList = new ArrayList<Grid>();
        if (isValidGrid(grid.x, grid.y-1, openList, closeList)) {
            gridList.add(new Grid(grid.x, grid.y - 1));
        }
        if (isValidGrid(grid.x, grid.y+1, openList, closeList)) {
            gridList.add(new Grid(grid.x, grid.y + 1));
        }
        if (isValidGrid(grid.x-1, grid.y, openList, closeList)) {
            gridList.add(new Grid(grid.x - 1, grid.y));
        }
        if (isValidGrid(grid.x+1, grid.y, openList, closeList)) {
            gridList.add(new Grid(grid.x + 1, grid.y));
        }
        return gridList;
    }

    private static boolean isValidGrid(int x, int y, List<Grid> openList, List<Grid> closeList) {
        //是否超过边界
        if (x < 0 || x >= MAZE.length || y < 0 || y >= MAZE[0].length) {
            return false;
        }
        //是否有障碍物
        if(MAZE[x][y] == 1){
            return false;
        }
        //是否已经在openList中
        if(containGrid(openList, x, y)){
            return false;
        }
        //是否已经在closeList中
        if(containGrid(closeList, x, y)){
            return false;
        }
        return true;
    }

    private static boolean containGrid(List<Grid> grids, int x, int y) {
        for (Grid grid : grids) {
            if ((grid.x == x) && (grid.y == y)) {
                return true;
            }
        }
        return false;
    }

    static class Grid {
        public int x;
        public int y;
        public int f;
        public int g;
        public int h;
        public Grid parent;

        public Grid(int x, int y) {
            this.x = x;
            this.y = y;
        }

        public void initGrid(Grid parent, Grid end){
            this.parent = parent;
            this.g = parent.g + 1;
            this.h = Math.abs(this.x - end.x) + Math.abs(this.y - end.y);
            this.f = this.g + this.h;
        }
    }

    public static void main(String[] args) {
        //设置起点和终点
        Grid startGrid = new Grid(2, 1);
        Grid endGrid = new Grid(2, 5);
        //搜索迷宫终点
        Grid resultGrid = aStarSearch(startGrid, endGrid);
        //回溯迷宫路径
        ArrayList<Grid> path = new ArrayList<Grid>();
        while (resultGrid != null) {
            path.add(new Grid(resultGrid.x, resultGrid.y));
            resultGrid = resultGrid.parent;
        }
        //输出迷宫和路径，路径用星号表示
        for (int i = 0; i < MAZE.length; i++) {
            for (int j = 0; j < MAZE[0].length; j++) {
                if (containGrid(path, i, j)) {
                    System.out.print("*, ");
                } else {
                    System.out.print(MAZE[i][j] + ", ");
                }
            }
            System.out.println();
        }
    }
}  

================================================
FILE: src/chapter6/part5/Redpackage.java
================================================
package chapter6.part5;

import java.math.BigDecimal;
import java.util.*;

/**
* Created by weimengshu on 2018/4/8.
*/
public class Redpackage {

    /**
     * 拆分红包
     * @param totalAmount  总金额（以分为单位）
     * @param totalPeopleNum  总人数
     */
    public static List<Integer> divideRedPackage(Integer totalAmount, Integer totalPeopleNum){
        List<Integer> amountList = new ArrayList<Integer>();
        Integer restAmount = totalAmount;
        Integer restPeopleNum = totalPeopleNum;
        Random random = new Random();
        for(int i=0; i<totalPeopleNum-1; i++){
            //随机范围：[1，剩余人均金额的两倍)，左闭右开
            int amount = random.nextInt(restAmount / restPeopleNum * 2 - 1) + 1;
            restAmount -= amount;
            restPeopleNum --;
            amountList.add(amount);
        }
        amountList.add(restAmount);
        return amountList;
    }

    /**
     * 拆分红包V2
     * @param totalAmount  总金额（以分为单位）
     * @param totalPeopleNum  总人数
     */
    public static List<Integer> divideRedPackageV2(Integer totalAmount, Integer totalPeopleNum){
        List<Integer> amountList = new ArrayList<Integer>();
        Set<Integer> segments = new HashSet<Integer>();
        Random random = new Random();
        for(int i = 0; i< totalPeopleNum-1; i++){
            int segment =  random.nextInt(totalAmount-2) + 1;
            int delta = random.nextInt(1)==0 ? 1 : -1;
            while(segments.contains(segment) || segment == 0){
                segment = (segment+delta)%totalAmount;
            }
            segments.add(segment);
        }

        List<Integer> segmentList = new ArrayList<Integer>(segments);
        Collections.sort(segmentList);
        for(int i=0; i<segmentList.size(); i++){
            Integer amount;
            if(i==0){
                amount = segmentList.get(0);
            }else {
                amount = segmentList.get(i) - segmentList.get(i-1) ;
            }
            amountList.add(amount);
        }
        amountList.add(totalAmount - segmentList.get(segmentList.size()-1));

        return amountList;
    }

    public static void main(String[] args){
        List<Integer> amountList = divideRedPackage(1000, 10);
        for(Integer amount : amountList){
            System.out.println("抢到金额：" + new BigDecimal(amount).divide(new BigDecimal(100)));
        }
    }
}