还是畅通工程 HDU - 1233

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 = ;
 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 = ; i <= n; i++){

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

 }

 int prime(int& n){

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

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

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

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

     int ans = ;
     for(int i = ; 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-)/;

         init(n);

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

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

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

     return ;
 }