UVA 567 Risk

最短路问题：floyd算法：

注意：输出格式

#include<stdio.h>
#define MAXN 200

int a, b, n, d[30][30], num;
void init()
{
    num = 0;
    while(scanf("%d",&a) == 1)
    {
        for(int i = 1; i <= 20; i ++)
            for(int j = 1; j <= 20; j ++)
                if(i == j) d[i][j] = 0;
                else d[i][j] = MAXN;
        if(a != 0)
            for(int i = 0; i < a; i ++)
            {
                scanf("%d",&b);
                d[1][b] = 1;
                d[b][1] = 1;
            }
        for(int i = 2; i < 20; i ++)
        {
            scanf("%d",&a);
            if(a != 0)
                for(int j = 0; j < a; j ++)
                {
                    scanf("%d",&b);
                    d[i][b] = 1;
                    d[b][i] = 1;
                }
        }
        for(int k = 1; k <= 20; k ++)
            for(int i = 1; i <= 20; i ++)
            {
                for(int j = 1; j <= 20; j ++)
                d[i][j] = (d[i][j] < (d[i][k] + d[k][j]) )? d[i][j] : (d[i][k] + d[k][j]);
            }
        num ++;
        printf("Test Set #%d\n",num);
        scanf("%d",&n);
        for(int i = 0; i < n; i ++)
        {
            scanf("%d%d",&a,&b);
            printf("%2d to %2d: %d\n",a,b,d[a][b]);
        }
        puts("");
    }    
}

int main()
{
    init();
    return 0;
}