kruskal模板

#include<bits/stdc++.h>
using namespace std;
struct node{
	int u,v,dis;
}a[200005];
bool vis[200005];
int fa[200005];
int get(int x){
	if(fa[x] == x) return x;
    return fa[x] = get(fa[x]);
}
void merge(int x,int y){fa[get(x)] = get(y);}
bool cmp(node a,node b){return a.dis < b.dis;}
int main(){
    int n,m; cin >> n >> m;
    for(int i = 1;i <= n;i++) fa[i] = i;
    for(int i = 1;i <= m;i++){
    	cin >> a[i].u >> a[i].v >> a[i].dis;
        vis[a[i].u] = true;
        vis[a[i].v] = true;
    }
    sort(a + 1,a + m + 1,cmp);
    int ans = 0;
    for(int i = 1;i <= m;i++){
    	if(get(a[i].u) != get(a[i].v)){
        	merge(get(a[i].u),get(a[i].v));
            ans += a[i].dis;
        }
    }
    for(int i = 1;i <= n;i++){
    	if(vis[i] == false){
        	cout << "orz";
            return 0;
        }
    }
    cout << ans;
    return 0;
}