图的递归dfs和队列bfs

package cn.itcast.graph;

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

public class DFS {
    public static void dfsByRecursive(int[][] graph) {
        int length = graph.length;
        boolean[] visited = new boolean[length];
        //如果是连通图
        //从0号节点开始dfs遍历
        dfs(graph, 0, visited);
        //如果是非连通图
        //需要用一个for循环，确保每一个节点都能被访问到
//        for (int i = 0; i < length; i++) {
//            dfs(graph,i,visited)
//        }
    }

    public static void dfs(int[][] graph, int vertex, boolean[] visited) {
        visited[vertex] = true;
        System.out.print(vertex + " ");
        int length = graph.length;
        for (int i = 0; i < length; i++) {
            if (!visited[i] && graph[vertex][i] == 1) {
                dfs(graph, i, visited);
            }
        }
    }

    public static void bfsByQueue(int[][] graph) {
        Queue<Integer> queue = new LinkedList<Integer>();
        int length = graph.length;
        boolean[] visited = new boolean[length];

        for (int i = 0; i < length; i++) {
            if (!visited[i]) {
                visited[i] = true;
                System.out.print(i + " ");
                queue.add(i);
                while (queue.size() != 0) {
                    Integer temp = queue.poll();
                    for (int j = 0; j < length; j++) {
                        if (!visited[j] && graph[temp][j] == 1) {
                            visited[j] = true;
                            System.out.print(j + " ");
                            queue.add(j);
                        }
                    }
                }
            }
        }
    }

    public static void main(String[] args) {
        //定义一个图：使用邻接矩阵
        int[][] graph = {{0, 1, 0, 0, 1, 0, 0, 0},
                {0, 0, 1, 1, 0, 0, 0, 0},
                {0, 0, 0, 1, 0, 0, 0, 0},
                {0, 0, 0, 0, 0, 0, 0, 0},
                {0, 0, 0, 0, 0, 1, 0, 1},
                {0, 0, 0, 0, 0, 0, 1, 0},
                {0, 0, 0, 0, 0, 0, 0, 0},
                {0, 0, 0, 0, 0, 0, 0, 0}};
        
//        int[][] graph = {
//                { 0, 1, 1, 0, 0 },
//                { 0, 0, 1, 0, 1 },
//                { 0, 0, 0, 0, 0 },
//                { 1, 1, 0, 0, 1 },
//                { 0, 0, 1, 0, 0 }
//        };

        dfsByRecursive(graph);
        System.out.println();
        bfsByQueue(graph);
    }
}