package com.wzs;

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

// 图的遍历
public class Graph {
	// 邻接矩阵存储图
	// --A B C D E F G H I
	// A 0 1 0 0 0 1 1 0 0
	// B 1 0 1 0 0 0 1 0 1
	// C 0 1 0 1 0 0 0 0 1
	// D 0 0 1 0 1 0 1 1 1
	// E 0 0 0 1 0 1 0 1 0
	// F 1 0 0 0 1 0 1 0 0
	// G 0 1 0 1 0 1 0 1 0
	// H 0 0 0 1 1 0 1 0 0
	// I 0 1 1 1 0 0 0 0 0

	// 顶点数
	private int number = 9;
	// 记录顶点是否被访问
	private boolean[] flag;
	// 顶点
	private String[] vertexs = { "A", "B", "C", "D", "E", "F", "G", "H", "I" };
	// 边
	private int[][] edges = { 
			{ 0, 1, 0, 0, 0, 1, 1, 0, 0 }, { 1, 0, 1, 0, 0, 0, 1, 0, 1 }, { 0, 1, 0, 1, 0, 0, 0, 0, 1 },
			{ 0, 0, 1, 0, 1, 0, 1, 1, 1 }, { 0, 0, 0, 1, 0, 1, 0, 1, 0 }, { 1, 0, 0, 0, 1, 0, 1, 0, 0 },
			{ 0, 1, 0, 1, 0, 1, 0, 1, 0 }, { 0, 0, 0, 1, 1, 0, 1, 0, 0 }, { 0, 1, 1, 1, 0, 0, 0, 0, 0 } 
			};

	// 图的深度遍历操作(递归)
	void DFSTraverse() {
		flag = new boolean[number];
		for (int i = 0; i < number; i++) {
			if (flag[i] == false) {// 当前顶点没有被访问
				DFS(i);
			}
		}
	}

	// 图的深度优先递归算法
	void DFS(int i) {
		flag[i] = true;// 第i个顶点被访问
		System.out.print(vertexs[i] + " ");
		for (int j = 0; j < number; j++) {
			if (flag[j] == false && edges[i][j] == 1) {
				DFS(j);
			}
		}
	}

	// 图的广度遍历操作
	void BFSTraverse() {
		flag = new boolean[number];
		Queue<Integer> queue = new LinkedList<Integer>();
		for (int i = 0; i < number; i++) {
			if (flag[i] == false) {
				flag[i] = true;
				System.out.print(vertexs[i] + " ");
				queue.add(i);
				while (!queue.isEmpty()) {
					int j = queue.poll();
					for (int k = 0; k < number; k++) {
						if (edges[j][k] == 1 && flag[k] == false) {
							flag[k] = true;
							System.out.print(vertexs[k] + " ");
							queue.add(k);
						}
					}
				}
			}
		}
	}

	// 测试
	public static void main(String[] args) {
		Graph graph = new Graph();
		System.out.println("图的深度遍历操作(递归):");
		graph.DFSTraverse();
		System.out.println("\n-------------");
		System.out.println("图的广度遍历操作:");
		graph.BFSTraverse();
	}
}

输出结果：

图的深度遍历操作(递归):
A B C D E F G H I 
-------------
图的广度遍历操作:
A B F G C I E D H