Agri-Net POJ

题目链接：https://vjudge.net/problem/POJ-1258

思路：

最小生成树板子题。

#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
const int N = (int)1e3;
const int inf = (int)1e9;
int g[N][N];
int dis[N];
bool vis[N];
int n;

struct node{
    int loc;
    int w;

    bool friend operator<(const node& a,const node& b){
        return a.w > b.w;
    }
};

priority_queue<node > que;

int prime(){

    for(int i = 1; i <= n; i++){
        vis[i] = 0;
        dis[i] = inf;
    }

    while(!que.empty()) que.pop();

    que.push(node{1,0});
    dis[1] = 0;

    while(!que.empty()){
        int u = que.top().loc;
        que.pop();
        vis[u] = 1;

        for(int v = 1; v <= n ; v++){
            if(!vis[v] && dis[v] > g[u][v]){
                dis[v] = g[u][v];
                que.push(node{v,dis[v]});
            }
        }
    }

    int ans = 0;
    for(int i = 1; i <= n; i++)
        ans += dis[i];

    return ans;
}

int main(){

    while(~scanf("%d",&n) && n){

        for(int i = 1; i <= n; i++)
            for(int j = 1; j <= n; j++)
                scanf("%d",&g[i][j]);

        printf("%d
",prime());
    }

    return 0;
}