Maintain

#include<stdio.h>
#include<map>
using namespace std;

int parent[210];

int find(int x){
    if(parent[x] == x)return x;
    return parent[x] = find(parent[x]);
}

void unions(int x,int y){
    int rx = find(x);
    int ry = find(y);
    parent[rx] = ry;
}

int main()
{
    multimap<int,pair<int,int> >mymap;
    int n,w;
    scanf("%d %d",&n,&w);

    for(int i = 0 ; i <= n ; i ++)parent[i] = i;

    for(int t = 0 ; t < w ; t ++){
        int cnt = n;
        int sum = 0;
        int u,v,d;
        scanf("%d %d %d",&u,&v,&d);
        mymap.insert({d,{u,v}});
        std::multimap<int,pair<int,int> >::iterator its = mymap.begin();

        int ce = 0;
        while(its != mymap.end()){
            u = its->second.first;
            v = its->second.second;
            d = its->first;
            if(find(u) != find(v)){
                unions(u,v);
                sum += d;
                ce++;
            }
            ++its;
        }
        if(ce < n - 1){
            printf("-1\n");
        }else{
            printf("%d\n",sum);
        }
        for(int i = 0 ; i <= n ; i ++){
            parent[i] = i;
        }
    }
    return 0;
}