グラフの深さ優先検索、および深さ優先検索

package org.structure.graph;

import java.util.*;

/**
 * 图 深度优先算法 广度优先遍历
 * @author cjj_1
 * @date 2020-09-03 11:10
 */
public class GraphDemo {
    
    
    ArrayList<String> vertexList;
    LinkedList<Integer> queue;
    Map<String,Integer> vertexMap ;
    boolean[] isVisited;
    int[][] edges ;
    int numOfEdges;
    public static void main(String[] args) {
    
    
        GraphDemo demo = new GraphDemo(5);
        String[] vertex = {
    
    "A","B","C","D","E"};
        for(String s:vertex){
    
    
            demo.inertVertex(s);
        }
       demo.addEdges(demo.vertexMap.get("A"),demo.vertexMap.get("B"),1);
        demo.addEdges(demo.vertexMap.get("B"),demo.vertexMap.get("C"),1);
        demo.addEdges(demo.vertexMap.get("A"),demo.vertexMap.get("D"),1);
        demo.addEdges(demo.vertexMap.get("A"),demo.vertexMap.get("E"),1);
        demo.addEdges(demo.vertexMap.get("B"),demo.vertexMap.get("C"),1);
        demo.addEdges(demo.vertexMap.get("D"),demo.vertexMap.get("C"),1);
        demo.printEdges();
       // demo.dfs();//深度优先
        demo.bfs();//广度优先算法
    }
    public  GraphDemo(int n){
    
    
        vertexList = new ArrayList<>(n);
        queue = new LinkedList<Integer>();
        vertexMap = new HashMap<String,Integer>(n);
        edges = new int[n][n];
        isVisited = new boolean[n];
        numOfEdges =0;
    }

    /**
     * 一个节点的广度优先遍历
     * @param index
     */
    public void bfs(int index){
    
    
        System.out.print(vertexList.get(index)+"=>");
        //加入队列
        queue.add(index);
        isVisited[index]=true;
        int v;//当前节点
        int w;//下驱
        while (!queue.isEmpty()){
    
    
            v = queue.removeFirst();
            w = getFisrtNear(v);
            while (w!=-1){
    
    
                if(!isVisited[w]){
    
    
                    System.out.print(vertexList.get(w)+">=");
                    isVisited[w]=true;
                    queue.addLast(w);
                }
                w = getNextNear(v,w);
            }
        }
    }
    public void bfs(){
    
    
        for (int i=0;i<vertexList.size();i++){
    
    
            if(!isVisited[i]){
    
    
                bfs(i);
            }
        }
    }

    /**
     * 一个节点的深度优先遍历
     * @param index
     */
    public void dfs(int index){
    
    
        System.out.print(vertexList.get(index)+"->");
        isVisited[index]= Boolean.TRUE;
        int w =getFisrtNear(index);
       while (w!=-1){
    
    
           if(!isVisited[w]){
    
    
               dfs(w);
           }
          w =  getNextNear(index,w);
       }
    }
    public void dfs(){
    
    
        for (int i=0;i<vertexList.size();i++){
    
    
            if(!isVisited[i]){
    
    
                dfs(i);
            }
        }
    }

    /**
     * 获取当前节点的第一个临节点
     * @param index
     * @return
     */
    public int getFisrtNear(int index){
    
    
        for (int j=0;j<vertexList.size();j++){
    
    
            if(edges[index][j]>0){
    
    
                return j;
            }
        }
        return -1;
    }

    /**
     * 获取当前节点的下一个节点的下标
     * @param index
     * @param now
     * @return
     */
    public int getNextNear(int index,int now) {
    
    
        for(int j = now+1;j<vertexList.size();j++){
    
    
            if(edges[index][j]>0){
    
    
                return j;
            }
        }
        return -1;
    }


    /**
     * 增加节点
     * @param vertex
     */
    public void inertVertex(String vertex){
    
    
        vertexMap.put(vertex,vertexMap.size());
        vertexList.add(vertex);
    }

    /**
     * 增加边
     * @param n
     * @param m
     * @param weigth
     */
    public void  addEdges(int n,int m,int weigth){
    
    
        edges[n][m] = weigth;
        edges[m][n] = weigth;
        numOfEdges++;
    }
    public int getVertexNum(){
    
    
        return vertexList.size();
    }
    public int getEdges(){
    
    
        return numOfEdges;
    }

    /**
     * 打印最后的矩阵
     */
    public void printEdges(){
    
    
        for (int row=0;row<edges.length;row++){
    
    
            for (int col=0;col<edges[row].length;col++){
    
    
                System.out.printf("%d\t",edges[row][col]);
            }
            System.out.println();
        }
    }
}