hdu-1874 畅通工程续---模板题

题目链接：

http://acm.hdu.edu.cn/showproblem.php?pid=1874

题目大意：

求起点到终点的最短距离

解题思路：

注意重边，其他的就是模板

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 1000 + 10;
const int INF = 0x3f3f3f3f;
int Map[maxn][maxn];
int v[maxn], d[maxn];
int n, m;

void dijkstra(int s, int t)
{
    memset(v, 0, sizeof(v));
    for(int i = 0; i <= n; i++)d[i] = (i == s ? 0 : INF);
    for(int i = 0; i < n; i++)
    {
        int x = -1, m = INF;
        for(int i = 0; i < n; i++)if(!v[i] && d[i] <= m)m = d[x = i];
        v[x] = 1;
        for(int i = 0; i < n; i++)
        {
            if(d[i] > d[x] + Map[x][i])
            {
                d[i] = d[x] + Map[x][i];
            }
        }
    }
    if(d[t] == INF)d[t] = -1;
    cout<<d[t]<<endl;
}

int main()
{
    while(scanf("%d%d", &n, &m) != EOF)
    {
        int u, v, w, s, t;
        memset(Map, INF, sizeof(Map));
        while(m--)
        {
            scanf("%d%d%d", &u, &v, &w);
            Map[u][v] = Map[v][u] = min(w, Map[u][v]);
        }
        scanf("%d%d", &s, &t);
        dijkstra(s, t);
    }
}