本文以實(shí)例形式講述了基于Java的圖的廣度優(yōu)先遍歷算法實(shí)現(xiàn)方法,具體方法如下:
用鄰接矩陣存儲(chǔ)圖方法:
1.確定圖的頂點(diǎn)個(gè)數(shù)和邊的個(gè)數(shù)
2.輸入頂點(diǎn)信息存儲(chǔ)在一維數(shù)組vertex中
3.初始化鄰接矩陣;
4.依次輸入每條邊存儲(chǔ)在鄰接矩陣arc中
輸入邊依附的兩個(gè)頂點(diǎn)的序號(hào)i,j;
將鄰接矩陣的第i行第j列的元素值置為1;
將鄰接矩陣的第j行第i列的元素值置為1;
廣度優(yōu)先遍歷實(shí)現(xiàn):
1.初始化隊(duì)列Q
2.訪問頂點(diǎn)v;visited[v]=1;頂點(diǎn)v入隊(duì)Q;
3.while(隊(duì)列Q非空)
v=隊(duì)列Q的隊(duì)頭元素出隊(duì);
w=頂點(diǎn)v的第一個(gè)鄰接點(diǎn)
while(w存在)
如果w未被訪問,則訪問頂點(diǎn)w;visited[w]=1;頂點(diǎn)w入隊(duì)列Q
w=頂點(diǎn)v的下一個(gè)鄰接點(diǎn)
實(shí)現(xiàn)代碼如下:
package com.teradata.lsw.sort;import java.util.ArrayList;import java.util.LinkedList;import java.util.List;import java.util.Queue;public class BFS {// 存儲(chǔ)節(jié)點(diǎn)信息private Object[] vertices;// 存儲(chǔ)邊的信息數(shù)組private int[][] arcs;// 邊的條數(shù)private int vexnum;// 記錄第i個(gè)節(jié)點(diǎn)是否被訪問過private boolean[] visited;//構(gòu)建一個(gè)臨時(shí)鏈表存已經(jīng)遍歷過的節(jié)點(diǎn)private List<Object> temp = new ArrayList<Object>();/*** @param args** @author TD_LSW*/public static void main(String[] args) {// TODO Auto-generated method stubBFS g = new BFS(8);Character[] vertices = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H' };g.addVertex(vertices);g.addEdge(0, 1);g.addEdge(0, 2);g.addEdge(1, 3);g.addEdge(1, 4);g.addEdge(3, 5);g.addEdge(4, 5);g.addEdge(2, 6);g.addEdge(2, 7);System.out.println("圖的廣度優(yōu)先遍歷:");g.bfs();}// 廣度優(yōu)先遍歷實(shí)現(xiàn)private void bfs() {// TODO Auto-generated method stubfor (int i = 0; i < vexnum; i++) {visited[i] = false;}Queue<Integer> q = new LinkedList<Integer>();for (int i = 0; i < vexnum; i++) {if (!visited[i]) {visited[i] = true;visit(i);q.add(i);while (!q.isEmpty()) {int j = (Integer) q.remove().intValue();//判斷如果全部遍歷完了就不需要循環(huán)了if (temp.size() == vexnum) {q.removeAll(q);return;}for (int k = this.firstAdjVex(j); k >= 0; k = this.nextAdjVex(j, k)) {if (!visited[k]) {q.add(k);visited[k] = true;visit(k);}}}}}}// 查找下一個(gè)節(jié)點(diǎn)public int firstAdjVex(int i) {for (int j = 0; j < vexnum; j++) {if (arcs[i][j] > 0)return j;}return -1;}public int nextAdjVex(int i, int k) {for (int j = k + 1; j < vexnum; j++) {if (arcs[i][j] > 0)return j;}return -1;}// 初始化圖的邊private void addEdge(int i, int j) {// TODO Auto-generated method stubif (i == j)return;arcs[i][j] = 1;arcs[j][i] = 1;}// 初始化圖的節(jié)點(diǎn)private void addVertex(Object[] object) {// TODO Auto-generated method stubthis.vertices = object;}// 圖的初始化public BFS(int n) {// TODO Auto-generated constructor stubvexnum = n;vertices = new Object[n];arcs = new int[n][n];visited = new boolean[n];for (int i = 0; i < vexnum; i++) {for (int j = 0; j < vexnum; j++) {arcs[i][j] = 0;}}}private void visit(int i) {// TODO Auto-generated method stubtemp.add(vertices[i]);System.out.print(vertices[i] + " ");}}
新聞熱點(diǎn)
疑難解答
圖片精選