floyd算法（hdu2544）

floyd算法（hdu2544）

#include <cstdio>
const int N = 105 ;
const int INF = 1e6 ;    //路口间的初始距离，看成无穷大，相当于断开
int graph[N][N] ;
int n , m ;
void floyd(){
    int s = 1 ;
    for (int k = 1 ; k <= n ; k ++){    //遍历每一个点作为中转点
        for (int i = 1 ; i <= n ; i ++){
            if (graph[i][k] != INF){
                for (int j = 1 ; j <= n ; j ++)
                    if (graph[i][j] > graph[i][k] + graph[k][j])
                        graph[i][j] = graph[i][k] + graph[k][j] ;
            }
        }
    }
    printf ("%d\n",graph[s][n]);
}  
int main(){
    while(~scanf ("%d%d",&n,&m)){
        if (n == 0 && m == 0)    return 0 ;
        for (int i = 1 ; i <= n ; i ++)
            for (int j = 1 ; j <= n ;  j ++)
                graph[i][j] = INF ;
        int a , b , c ;
        while(m --){
            scanf ("%d%d%d",&a,&b,&c) ;
            graph[a][b] = c ;
            graph[b][a] = c ; //邻接矩阵存图
        }
        floyd() ;      
    }
    return 0 ;
}