弗洛伊德算法--最短路径

算法如下：

import java.util.Scanner;

public class Floyd {

public static void main(String[] args) {
// 测试数据
// 9 16
// 0 1 1
// 0 2 5
// 1 3 7
// 1 4 5
// 2 4 1
// 2 5 7
// 1 2 3
// 3 4 2
// 4 5 3
// 3 6 3
// 4 6 6
// 4 7 9
// 5 7 5
// 6 7 2
// 6 8 7
// 7 8 4
Scanner scan = new Scanner(System.in);
int m = scan.nextInt();
int edges = scan.nextInt();
int[][] arr = new int[m][m];
for(int i =0;i<m;i++){
for(int j=0;j<m;j++){
if(i==j){
arr[i][j]=0;
}else{
arr[i][j]=65535;
}
}
}
int begin,end,weight;
for(int i=0;i<edges;i++){
begin=scan.nextInt();
end=scan.nextInt();
weight=scan.nextInt();
arr[begin][end] = weight;
arr[end][begin] = weight;
}
//测试0到8
shortestPath_Floyd(arr,0,8);
}

public static void shortestPath_Floyd(int[][] arr,int begin,int end){
int[][] pathMatirx
9565
= new int[arr.length][arr.length] ;
int[][] shortPathTable = new int[arr.length][arr.length];
for(int v=0;v<arr.length;v++){
for(int w=0;w<arr.length;w++){
shortPathTable[v][w]=arr[v][w];
pathMatirx[v][w]=w;
}
}

for(int k=0;k<arr.length;k++){
for(int v=0;v<arr.length;v++){
for(int w=0;w<arr.length;w++){
if(shortPathTable[v][w]>shortPathTable[v][k]+shortPathTable[k][w]){
shortPathTable[v][w]=shortPathTable[v][k]+shortPathTable[k][w];
pathMatirx[v][w] = pathMatirx[v][k];
}
}
}
}
int mark;
System.out.println("begin:"+begin+" "+"end:"+end+" "+"weight:"+shortPathTable[begin][end]);
mark = pathMatirx[begin][end];
System.out.print(begin);
while(mark!=end){
System.out.print("-->"+mark);
mark=pathMatirx[mark][end];
}
System.out.println("-->"+end);
}
}