POJ 2570 传递闭包 Floyd

题意：

n个点

下面边以(0,0)输入结尾

u v 字母，表示u v间有 xx个字母

问：

(0,0)输入结尾

问 u v间的路径都存在的字母有哪些，输出这些字母

#include <cstdio>  
#include <cstring>  
#include <iostream>  
#include <math.h>  
#include <queue>  
#define N 250  
#define M N*N+2  
#define inf64 0x7ffffff  
#define inf 0x7ffffff  
using namespace std;  
  
inline int Min(int a,int b){return a>b?b:a;}  
int map[N][N];  
int main()  
{  
    int n,u,v;  
    char name[30];  
  
    while(scanf("%d",&n),n){  
        memset(map,0,sizeof(map));  
        scanf("%d %d ",&u,&v);  
        while(u!=0 && v!=0){  
            scanf("%s",name);  
            for(int i=0;i<strlen(name);i++)  
                map[u][v]|=1<<(name[i]-'a');  
  
            scanf("%d%d",&u,&v);  
        }  
            for (int k = 1;k <= n;k ++)                //floyd  
                for (int i = 1;i <= n;i ++)  
                    for (int j = 1;j <= n;j ++)  
                        if (map[i][k]&map[k][j])  
                            map[i][j] = map[i][j]|(map[i][k]&map[k][j]);  
  
            scanf("%d %d",&u,&v);  
            while(u!=0 && v!=0){  
                if(map[u][v]){  
                for(int i=0;i<30;i++)if(map[u][v]&(1<<i))printf("%c",i+'a');  
                }  
                else printf("-");  
                puts("");  
                scanf("%d %d",&u,&v);  
            }  
            puts("");  
    }  
    return 0;  
}  
/* 
3 
1 2 abc 
2 3 ad 
1 3 b 
3 1 de 
0 0 
1 3 
2 1 
3 2 
0 0 
2 
1 2 z 
0 0 
1 2 
2 1 
0 0 
*/

补充：软件开发 , C++ ,