图的递归dfs和队列bfs 

 1 package cn.itcast.graph;
 2 
 3 import java.util.LinkedList;
 4 import java.util.Queue;
 5 
 6 public class DFS {
 7     public static void dfsByRecursive(int[][] graph) {
 8         int length = graph.length;
 9         boolean[] visited = new boolean[length];
10         //如果是连通图
11         //从0号节点开始dfs遍历
12         dfs(graph, 0, visited);
13         //如果是非连通图
14         //需要用一个for循环，确保每一个节点都能被访问到
15 //        for (int i = 0; i < length; i++) {
16 //            dfs(graph,i,visited)
17 //        }
18     }
19 
20     public static void dfs(int[][] graph, int vertex, boolean[] visited) {
21         visited[vertex] = true;
22         System.out.print(vertex + " ");
23         int length = graph.length;
24         for (int i = 0; i < length; i++) {
25             if (!visited[i] && graph[vertex][i] == 1) {
26                 dfs(graph, i, visited);
27             }
28         }
29     }
30 
31     public static void bfsByQueue(int[][] graph) {
32         Queue<Integer> queue = new LinkedList<Integer>();
33         int length = graph.length;
34         boolean[] visited = new boolean[length];
35 
36         for (int i = 0; i < length; i++) {
37             if (!visited[i]) {
38                 visited[i] = true;
39                 System.out.print(i + " ");
40                 queue.add(i);
41                 while (queue.size() != 0) {
42                     Integer temp = queue.poll();
43                     for (int j = 0; j < length; j++) {
44                         if (!visited[j] && graph[temp][j] == 1) {
45                             visited[j] = true;
46                             System.out.print(j + " ");
47                             queue.add(j);
48                         }
49                     }
50                 }
51             }
52         }
53     }
54 
55     public static void main(String[] args) {
56         //定义一个图：使用邻接矩阵
57         int[][] graph = {{0, 1, 0, 0, 1, 0, 0, 0},
58                 {0, 0, 1, 1, 0, 0, 0, 0},
59                 {0, 0, 0, 1, 0, 0, 0, 0},
60                 {0, 0, 0, 0, 0, 0, 0, 0},
61                 {0, 0, 0, 0, 0, 1, 0, 1},
62                 {0, 0, 0, 0, 0, 0, 1, 0},
63                 {0, 0, 0, 0, 0, 0, 0, 0},
64                 {0, 0, 0, 0, 0, 0, 0, 0}};
65         
66 //        int[][] graph = {
67 //                { 0, 1, 1, 0, 0 },
68 //                { 0, 0, 1, 0, 1 },
69 //                { 0, 0, 0, 0, 0 },
70 //                { 1, 1, 0, 0, 1 },
71 //                { 0, 0, 1, 0, 0 }
72 //        };
73 
74         dfsByRecursive(graph);
75         System.out.println();
76         bfsByQueue(graph);
77     }
78 }

 

posted @ 2020-12-18 17:07  myhuang  阅读(98)  评论(0)    收藏  举报