CUBE-121: COI Great Raid

#include <bits/stdc++.h>
using namespace std;
int n,m;
int parent[100001];
int find(int u) {
    if (parent[u] == u)
        return u;
    return parent[u] = find(parent[u]);
}
void merge(int u, int v) {
    u = find(u), v = find(v);
    if (u == v)
        return ;
    parent[u] = v;
}
struct Edge {
    int u,v,w;
    bool operator <(const Edge & rhs) const{
        return w< rhs.w;
    }
};
vector <Edge> edges;
int main(){
    scanf("%d",&n);
    int weight[n+1];
    for(int i=1;i<=n;i++){
        scanf("%d ",&weight[i]);
    }
    scanf("%d",&m);
    for(int i=1;i<=m;i++){
        int u,v;
        scanf("%d %d",&u,&v);
        edges.push_back({u,v,weight[u]+weight[v]});
        parent[u]=u;
        parent[v]=v;
    }
    sort(edges.begin(),edges.end());
    int sum=0;
    for(auto edge : edges){
        if(find(edge.u)==find(edge.v))
            continue;
        sum+=edge.w;
        merge(edge.u,edge.v);
    }
    printf("%d",sum);
    return 0;
}