数组结构与算法

package com.semanteme.demo.tree;

import java.util.*;

public class TreeBase {

    public static void main(String[] args) {

        Node root = new Node(7);

        Node node2 = new Node(5);
        root.setLeft(node2);
        Node node1 = new Node(11);
        root.setRight(node1);

        Node node3 = new Node(6);
        node2.setRight(node3);
        Node node4 = new Node(2);
        node2.setLeft(node4);

        Node node5 = new Node(3);
        node4.setRight(node5);
        Node node6 = new Node(1);
        node4.setLeft(node6);

        Node node7 = new Node(13);
        node1.setRight(node7);
        Node node8 = new Node(9);
        node1.setLeft(node8);

        Node node9 = new Node(14);
        node7.setRight(node9);
        Node node10 = new Node(12);
        node7.setLeft(node10);

        NodeUtil nodeUtil = new NodeUtil();

        nodeUtil.preOrder(root);
        System.out.println("====================");
        nodeUtil.inOrder(root);
        System.out.println("====================");
        nodeUtil.sufOrder(root);
        System.out.println("====================");

        List<Node> list = new ArrayList<>();
        list.add(root);
        nodeUtil.levelOrder(list);
        nodeUtil.levelOrderTraversal(root);
    }

}

class NodeUtil{

    /**
     * 前序遍历
     * @param node
     */
    public void preOrder(Node node) {

        System.out.print(node.getValue() + " ");

        if(node.getLeft() != null){
            preOrder(node.getLeft());
        }

        if(node.getRight() != null){
            preOrder(node.getRight());
        }
    }

    /**
     * 中序遍历
     * @param node
     */
    public void inOrder(Node node) {

        if(node.getLeft() != null){
            inOrder(node.getLeft());
        }

        System.out.print(node.getValue() + " ");

        if(node.getRight() != null){
            inOrder(node.getRight());
        }
    }

    /**
     * 后续遍历
     * @param node
     */
    public void sufOrder(Node node){

        if(node.getLeft() != null){
            sufOrder(node.getLeft());
        }

        if(node.getRight() != null){
            sufOrder(node.getRight());
        }

        System.out.print(node.getValue() + " ");
    }

    /**
     * 层级遍历
     *
     * @param list
     */
    public void levelOrder(List<Node> list){

        ArrayList<Node> nextList = new ArrayList<>();

        for (Node node : list) {

            System.out.print(node.getValue() + " ");

            if(node.getLeft() != null){
                nextList.add(node.getLeft());
            }

            if(node.getRight() != null){
                nextList.add(node.getRight());
            }
        }
        System.out.println("====================");

        if(!nextList.isEmpty()){
            levelOrder(nextList);
        }
    }

    public void levelOrderTraversal(Node node){

        Queue<Node> queue = new LinkedList<>();
        queue.add(node);

        while (!queue.isEmpty()){

            Node poll = queue.poll();
            System.out.print(poll.getValue() + " ");

            if(poll.getLeft() != null){
                queue.add(poll.getLeft());
            }

            if(poll.getRight() != null){
                queue.add(poll.getRight());
            }

        }
    }
}

class Node{

    private int value;

    private Node root;

    private Node left;

    private Node right;

    public Node() {
    }

    public Node(int value) {
        this.value = value;
    }

    public Node(int value, Node left, Node right) {
        this.value = value;
        this.left = left;
        this.right = right;
    }

    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }

    public Node getLeft() {
        return left;
    }

    public void setLeft(Node left) {
        this.left = left;
    }

    public Node getRight() {
        return right;
    }

    public void setRight(Node right) {
        this.right = right;
    }

    public Node getRoot() {
        return root;
    }

    public void setRoot(Node root) {
        this.root = root;
    }



    @Override
    public String toString() {
        return "Node{" +
                "value=" + value +
                '}';
    }
}

平衡二叉树（AVL树）

左旋
右旋

多路查找树

图

图的表示
深度优先遍历（DFS）
广度优先遍历（BFS）

算法

二分查找算法

递归写法
非递归写法
汉诺塔游戏算法

动态规划

背包

KMP

贪心算法

普利姆算法

修路最短

克鲁斯卡尔算法

迪杰斯特拉算法

弗洛伊德算法

马踏棋盘

java 复制代码

package com.semanteme.demo.dst;


import java.util.ArrayList;
import java.util.List;

public class HorseChessBoard  {

    public static void main(String[] args) {
        int X = 8;
        int Y = 8;

        ChessBoard chessBoard = new ChessBoard(X, Y);
        System.out.println("周游前===========");
        chessBoard.show();

        long startTime = System.currentTimeMillis();
        chessBoard.travel(3, 2, 1);
        System.out.println("周游后===========;总共耗时：" + (System.currentTimeMillis() - startTime));
        chessBoard.show();

    }



}

class ChessBoard {

    private int X;
    private int Y;
    private int[][] chessBoard;

    private boolean[] visitChess;

    private boolean isFinished;

    public ChessBoard(int X, int Y){
        this.X = X;
        this.Y = Y;
        this.chessBoard = new int[X][Y];
        this.visitChess = new boolean[X * Y];
    }

    public void travel(int row, int col, int step){

        chessBoard[row][col] = step;
        visitChess[row * Y + col] = true;

        List<Coordinate> next = next(new Coordinate(row, col));
        sort(next);

        while (!next.isEmpty()){
            Coordinate remove = next.remove(0);

            // 未被访问过
            if(!visitChess[remove.getRow() * Y + remove.getCol()]){
                travel(remove.getRow(), remove.getCol(), step+1);
            }

        }

        if(step < X * Y && !isFinished){
            chessBoard[row][col] = 0;
            visitChess[row * Y + col] = false;
        }else {
            isFinished = true;
        }
    }

    private void sort(List<Coordinate> list){
        list.sort((o1, o2) -> {

            List<Coordinate> next1 = next(o1);
            List<Coordinate> next2 = next(o2);
            return next1.size() - next2.size();
        });
    }

    private List<Coordinate> next(Coordinate p){

        List<Coordinate> nextPoints = new ArrayList<>(8);

        // 添加0位置
        if(p.getRow() - 1 >= 0 && p.getCol() + 2 < Y){
            Coordinate point = new Coordinate(p.getRow() - 1, p.getCol() + 2);
            nextPoints.add(point);
        }

        // 添加1位置
        if(p.getRow() + 1 < X && p.getCol() + 2 < Y){
            Coordinate point = new Coordinate(p.getRow() + 1, p.getCol() + 2);
            nextPoints.add(point);
        }

        // 添加2位置
        if(p.getRow() + 2 < X && p.getCol() + 1 < Y){
            Coordinate point = new Coordinate(p.getRow() + 2, p.getCol() + 1);
            nextPoints.add(point);
        }

        // 添加3位置
        if(p.getRow() + 2 < X && p.getCol() - 1 >= 0){
            Coordinate point = new Coordinate(p.getRow() + 2, p.getCol() - 1);
            nextPoints.add(point);
        }

        // 添加4位置
        if(p.getRow() + 1 < X && p.getCol() - 2 >= 0){
            Coordinate point = new Coordinate(p.getRow() + 1, p.getCol() - 2);
            nextPoints.add(point);
        }

        // 添加5位置
        if(p.getRow() - 1 > 0 && p.getCol() - 2 >= 0){
            Coordinate point = new Coordinate(p.getRow() - 1, p.getCol() - 2);
            nextPoints.add(point);
        }

        // 添加6位置
        if(p.getRow() - 2 >= 0 && p.getCol() - 1 >= 0){
            Coordinate point = new Coordinate(p.getRow() - 2, p.getCol() - 1);
            nextPoints.add(point);
        }

        // 添加7位置
        if(p.getRow() - 2 >= 0 && p.getCol() + 1 < Y){
            Coordinate point = new Coordinate(p.getRow() - 2, p.getCol() + 1);
            nextPoints.add(point);
        }

        return nextPoints;
    }

    public void show() {
        for (int[] chess : chessBoard) {
            for (int i : chess) {
                System.out.print(i + " ");
            }
            System.out.println();
        }
    }
}

/**
 * 坐标
 */
class Coordinate{

    public int row;

    public int col;

    public Coordinate(int row, int col) {
        this.row = row;
        this.col = col;
    }

    public int getRow() {
        return row;
    }

    public void setRow(int row) {
        this.row = row;
    }

    public int getCol() {
        return col;
    }

    public void setCol(int col) {
        this.col = col;
    }

    @Override
    public String toString() {
        return "Coordinate{" +
                "row=" + row +
                ", col=" + col +
                '}';
    }
}

数组结构与算法

文章目录

数据结构与算法

快速排序思路

树

赫夫曼树 （HuffmanTree）

二叉排序树（Binary sort tree）

构建二叉树

遍历二叉树

平衡二叉树（AVL树）

多路查找树

图

算法

二分查找算法

动态规划

KMP

贪心算法

普利姆算法

克鲁斯卡尔算法

迪杰斯特拉算法

弗洛伊德算法

马踏棋盘

赫夫曼树（HuffmanTree）