Til the Cows Come Home POJ

题目链接：https://cn.vjudge.net/problem/POJ-2387#author=dusenlin

注意：输入的时候，两点之间可能有多条边，选则边权最小的

#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
#include <stack>
#include <algorithm>
#include <cmath>
#include <map>
#define mem(a,b) memset(a,b,sizeof(a));
using namespace std;
#define INF 0x3f3f3f3f
typedef long long ll;
int dir[4][2] = {0,1,0,-1,1,0,-1,0};
const int maxn = 5000005;
int t,n,edge[1005][1005],d[1005],vis[1005];
void Dijkstra(int s) {
    mem(vis,0);
    mem(d,INF);
    d[1] = 0;
    for(int i = 1; i <= n; i++) {
        int maxn = INF,x;
        for(int j = 1; j <= n; j++) {
            if(d[j] < maxn&&!vis[j]) {
                maxn = d[j];
                x = j;
            }
        }
        vis[x] = 1;
        for(int j = 1; j <= n; j++) {
            d[j] = min(d[j],d[x]+edge[x][j]);
        }
    }
}
int main(){
    cin >> t >>n;
    int a,b,c;
    mem(edge,INF);
    for(int i = 0; i < t; i++) {
        cin >> a >> b >> c;
        if(c < edge[a][b]){
        edge[a][b] = c;
        edge[b][a] = c;
        }
    }
    Dijkstra(1);
    cout << d[n] << endl;
    return 0;
}