还是畅通工程 HDU

题目链接：https://vjudge.net/problem/HDU-1233

思路：

最小生成树板子。

#include <iostream>
#include <stdio.h>
#include <queue>
using namespace std;

const int N = 110;
const int inf = (int)1e9;
int g[N][N];
bool vis[N];
int dis[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;

void init(int& n){

    for(int i = 1; i <= n; i++){

        dis[i] = inf;
        vis[i] = 0;
        for(int j = 1; j <= n; j++)
            if(i == j) g[i][j] = 0;
            else g[i][j] = inf;
    }

}

int prime(int& n){

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

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

    int u;
    while(!que.empty()){
        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(){

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

        int u,v,w;
        int len = n*(n-1)/2;

        init(n);

        for(int i = 1; i <= len; i++){
            scanf("%d%d%d",&u,&v,&w);

            if(g[u][v] > w)
                g[u][v] = g[v][u] = w;
        }

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


    return 0;
}