图的两种遍历-Java

图遍历基本就是广度优先和深度优先，基本思想和树遍历一致。需要注意的一点就是图的连通性，有时从图中一点出发并不能到达所有节点。

import java.util.*;

public class Graph {
    private static int [][] graph;
    private static int size;
    static int[] isVisited = new int[10];
    public static void main(String[] args) {
        graph = new int[][]{
                {0, 0, 1, 1, 0, 0},
                {0, 0, 1, 0, 0, 0},
                {1, 1, 0, 0, 0, 0},
                {0, 0, 1, 0, 1, 0},
                {0, 0, 0, 1, 0, 1},
                {0, 0, 0, 0, 1, 0}
        };
        size = graph.length;
        BFS();
    }
    static void BFS(int[][] graph, int idx){
        Queue<Integer> queue = new LinkedList<>();
        System.out.println(idx);
        queue.offer(idx);
        isVisited[idx] = 1;
        while(!queue.isEmpty()){
            int u = queue.poll();
            for(int i =0;i<graph[idx].length;i++){
                if(i!=u&&graph[u][i]==1&&isVisited[i]==0){
                    isVisited[i] = 1;
                    System.out.println(i);
                    queue.offer(i);
                }
            }
        }
    }

    static void DFS(int[][] graph, int idx){
        isVisited[idx] = 1;
        System.out.println(idx);
        for(int i =0;i<graph[idx].length;i++){
            if(isVisited[i]==0&&i!=idx&&graph[idx][i]==1){
                DFS(graph, i);
            }
        }
    }

    public static void BFS(){
        for(int i=0;i<size;i++){
            if(isVisited[i]==0){
                BFS(graph, i);
            }
        }
    }

    public static void DFS(){
        for(int i =0;i<size;i++){
            if(isVisited[i]==0){
                DFS(graph, i);
            }
        }
    }
}