Dijkstra算法

 1 package com.gxf.graph;
 2 
 3 /**
 4  * @author xiangfei
 5  *
 6  */
 7 public class Graph {
 8     //这里用邻接矩阵存储图
 9     int cost[][] = new int[6][6];
10     int max = 1000;
11     int dist[] = new int[6];
12     public Graph(){
13         //初始化矩阵
14         for(int i = 0; i < 6; i++){
15             for(int j = 0; j < 6; j++){
16                 cost[i][j] = max;
17             }
18         }//for
19         cost[0][2] = 10;
20         cost[0][4] = 30;
21         cost[0][5] = 100;
22         cost[2][3] = 50;
23         cost[3][5] = 10;
24         cost[4][3] = 20;
25         cost[4][5] = 60;
26     }
27     
28     /**
29      * 获取v到其他顶点最短距离保存到数组dist[]中
30      * @param v
31      */
32     public void shotPath(int v){
33         boolean s[] = new boolean[6];//s保存是否已经求出最短距离节点
34         
35         //初始化
36         for(int i = 0; i < 6; i++){
37             s[i] = false;
38             if(cost[v][i] < max){
39                 dist[i] = cost[v][i];
40             }
41             else{
42                 dist[i] = max;
43             }
44         }//for
45         s[v] = false;
46         //开始找到每个节点的最短距离，根据算法思想至少要n - 1次
47         for(int i = 0; i < 5; i++){
48             int tempMin = max;
49             int k = i;//存放最小距离的顶点
50             //找出最短的，加入s集合中
51             for(int j = 0; j < 6; j++){
52                 if(!s[j] && dist[j] < tempMin){//在未求出最短距离的集合中找
53                     tempMin = dist[j];
54                     k = j;
55                 }
56             }
57             s[k] = true;
58             //更新dist[]数组
59             for(int j = 0; j < 6; j++){
60                 if(!s[j] && dist[j] > dist[k] + cost[k][j]){
61                     dist[j] = dist[k] + cost[k][j];
62                 }
63             }
64         }
65         
66     }
67     /**
68      * 输出矩阵内容
69      */
70     public void showCost(){
71         System.out.println("矩阵内容是：");
72         for(int i = 0; i < 6; i++){
73             for(int j = 0; j < 6; j++){
74                 System.out.print(cost[i][j] + "\t");
75             }
76             System.out.println();
77         }//for
78     }
79     
80     /**
81      * 测试方法
82      * @param args
83      */
84     public static void main(String args[]){
85         Graph graph = new Graph();
86         graph.showCost();
87         graph.shotPath(0);
88         for(int i = 0; i < graph.dist.length;i++){
89             System.out.println("顶点0" + "到 顶点" + i + "的最短距离是：" + graph.dist[i]);
90         }
91     }
92 }