hdu 1385 Floyd 输出路径

Floyd 输出路径

Sample Input
5
0 3 22 -1 4
3 0 5 -1 -1
22 5 0 9 20
-1 -1 9 0 4
4 -1 20 4 0
5 17 8 3 1 //收费
1 3 //起点 终点
3 5
2 4
-1 -1
0

Sample Output
From 1 to 3 :
Path: 1-->5-->4-->3
Total cost : 21

From 3 to 5 :
Path: 3-->4-->5
Total cost : 16

From 2 to 4 :
Path: 2-->1-->5-->4
Total cost : 17

# include <iostream>
# include <cstdio>
# include <cstring>
# include <string>
# include <algorithm>
# include <cmath>
# include <map>
# define LL long long
using namespace std ;

const int MAXN = 310 ;
const int INF = 0x3f3f3f3f;
int dis[MAXN][MAXN];
int b[MAXN] ;
int path[MAXN][MAXN] ;
int n ;

void floyed()//节点从1~n编号
{
    int i,j,k;
    for (i = 1; i <= n; i++)
        for (j = 1; j <= n; j++)
            path[i][j] = j;  //记录路径数组初始化，表示从i到j经过的第一个站
    for(k=1;k<=n;k++)
       for(i=1;i<=n;i++)
         for(j=1;j<=n;j++)
         {
             int t = dis[i][k]+dis[k][j] + b[k] ;
             if (t < dis[i][j])
             {
                 dis[i][j] = t ;
                 path[i][j] = path[i][k] ;
             }
             else if (t == dis[i][j] && path[i][k] < path[i][j])
                 path[i][j] = path[i][k] ;

         }


}

int main()
{
   // freopen("in.txt","r",stdin) ;
    while (scanf("%d" , &n) , n)
    {
        int i , j ;
        for (i = 1 ; i <= n ; i++)
            for (j = 1 ; j <= n ; j++)
        {
            scanf("%d" , &dis[i][j]) ;
            if (dis[i][j] == -1)
                dis[i][j] = INF ;
        }
        for (i = 1 ; i <= n ; i++)
            scanf("%d" , &b[i]) ;
        floyed() ;
        int u , v ;
        while(scanf("%d %d" , &u , &v) )
        {
            if (u == -1 && v == -1)
                break ;
            printf ("From %d to %d :
", u, v);
            printf ("Path: %d", u);
            int t = u;
            while (u != v)
            {
                printf ("-->%d", path[u][v]);
                u = path[u][v];
            }
            printf ("
Total cost : %d

", dis[t][v]);
        }

    }
    return 0;
}