hdoj 2066 一个人的旅行

最短路问题，把0（小草所在的）城市与相邻城市设置为0，然后就是求出每想去城市的最短路径，从每个最短路径中取出最小值

#include <stdio.h>
#define min(a, b) a < b ? a : b
#define inf 0x7FFFFFFF
#define M 1001

int map[M][M];
int dist[M];
int visit[M];

int t, s, d, k;

int mdist(int res, int des) //最短路函数
{
    int i = 0;
    for (i = 0; i < M; i++)
    {
        dist[i] = inf;
        visit[i] = inf;
    }
    visit[res] = 0;
    dist[res] = 0;
    while (res != des)
    {
        int min = inf, next, f = 0;
        for (i = 0; i < M; i++)
        {
            if (map[res][i] != inf)
            {
                dist[i] = min(dist[i], dist[res] + map[res][i]);
            }
            if (visit[i] && min > dist[i])
            {
                min = dist[i];
                next = i;
            }
        }
        if (min == inf)
            break;
        res = next;
        visit[res] = 0;
    }
    return dist[des];
}
int main()
{
    while (scanf("%d %d %d", &t, &s, &d) != -1)
    {
        int i, j, a, b, l;
        for (i = 0; i < M; i++)
        {
            for (j = 0; j < M; j++)
                map[i][j] = inf;
        }

        for (i = 0; i < t; i++)
        {
            scanf("%d %d %d", &a, &b, &l);
            map[a][b] = map[b][a] = min(map[a][b], l);
        }

        for (i = 0; i < s; i++)
        {
            scanf("%d", &a);
            map[a][0] = map[0][a] = 0;
        }
        int min = inf, kk;
        for (i = 0; i < d; i++)
        {
            scanf("%d", &a);
            kk = mdist(0, a);
            if (min > kk)
                min = kk;
        }
        printf("%d\n", min);
    }
    return 0;
}