HDU_2066 一个人的旅行（Dijkstra）

　　开始用Floyd做的，TLE！更二的时我自己找了一组1 1000 的数据，4S才算出来，本身程序就有问题，我居然还交上去了。。。后来用Dijkstra做，过了。。。200+ms；

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

const int N = 1005;
const int inf = 1000000;

int dis[N][N];
int low[N];
int vis[N];
int num1[N];
int num2[N];

void Dijkstra(int n, int v)
{
    int flag, min, i, j;
    for(i = 1; i <= n; i++)
    {
        low[i] = dis[v][i];
        vis[i] = 0;
    }

    vis[v] = 1;
    for(i = 2; i <= n; i++)
    {
        min = inf; flag = v;
        for(j = 2; j <= n; j++)
        {
            if(min > low[j] && !vis[j])
            {
                min = low[j];
                flag = j;
            }
        }
        vis[flag] = 1;

        for(j = 2; j <= n; j++)
            if(!vis[j] && dis[flag][j] < inf)
            {
                int tmp = low[flag] + dis[flag][j];
                if(tmp < low[j])
                    low[j] = tmp;
            }
    }

}
int main()
{
    //freopen("data.in", "r", stdin);

    int t, s, d;
    while(~scanf("%d%d%d", &t, &s, &d))
    {
        int a, b, c, i, j, max = -inf;

        for(i = 1; i <= N; i++)
            for(j = 1; j <= N; j++)
            {
                if(i == j)
                    dis[i][j] = 0;
                else
                    dis[i][j] = inf;
            }

        for(i = 1; i <= t; i++)
        {
            scanf("%d%d%d", &a, &b, &c);
            if(c < dis[a][b])
                dis[a][b] = dis[b][a] = c;
            if(max < a)    max = a;
            if(max < b)    max = b;
        }

        for(i = 1; i <= s; i++)
            scanf("%d", &num1[i]);

        for(i = 1; i <= d; i++)
            scanf("%d", &num2[i]);

        int min = inf;
        for(i = 1; i <= s; i++)
        {
            Dijkstra(max, num1[i]);
            for(j = 1; j <= d; j++)
            {
                if(min > low[num2[j]])
                    min = low[num2[j]];
            }
        }
        printf("%d\n", min);
    }
}