就这个Prim爽！

#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
#include <memory.h>
#define double pair <int, int>
using namespace std;
vector <double> v[5005];
bool vis[5005];
int n, m, x, y, z;
int prim(){
	int ct = 0, ctt = 0;
	priority_queue <double, vector <double>, greater <double>> q;
	q.push({0, 1});
	while(!q.empty()){
		double head = q.top();
		q.pop();
		if(vis[head.second]) continue;
		vis[head.second] = 1, ctt++, ct += head.first;
		for(double it:v[head.second]){
			if(!vis[it.first]) q.push({it.second, it.first});
		}
	}
	return (ctt < n ? -1 : ct);
}
int read(){
	char c = getchar();
	int x = 0, f = 1;
	while(!isdigit(c)){
		if(c == '-') f = -f;
		c = getchar();
	}
	while(isdigit(c)){
		x = (x << 3) + (x << 1) + c - '0';
		c = getchar();
	}
	return x * f;
}
int main(){
	n = read(), m = read();
	for(int i = 1; i <= m; i++){
		x = read(), y = read(), z = read();
		v[x].push_back({y, z}), v[y].push_back({x, z});
	}
	int ans = prim();
	if(ans == -1) cout << "orz";
	else cout << ans;

	return 0;
}