COI great raid

#include<stdio.h>
#include<queue>
using namespace std;
typedef long long int ll;

struct edge{
    int u,v;
    ll dif;
    bool operator < (const edge& rhs)const
    {
        return dif > rhs.dif;
    }
};

int set[100010];
int find(int x){
    if(set[x] == x)return x;
    return set[x] = find(set[x]);
}
void unions(int x,int y){
    int rx = find(x);
    int ry = find(y);
    set[rx] = ry;
}
bool isset(int x,int y){
    return find(x) == find(y);
}



int main()
{
    for(int i=0;i<=100000;i++)set[i] = i;
    int n,m;
    scanf("%d",&n);
    int str[n+1];
    for(int i=1;i<=n;i++)scanf("%lld",&str[i]);
    scanf("%d",&m);

    priority_queue<edge> pq;
    for(int i=1;i<=m;i++){
        int u,v;
        scanf("%d %d",&u,&v);
        pq.push({u,v,str[u] + str[v]});
    }
    ll sum = 0;
//  printf("%d\n",pq.size());
    while(!pq.empty()){
        int u = pq.top().u;
        int v = pq.top().v;
        ll t = pq.top().dif;
        pq.pop();
    //  printf("Test %d %d %lld\n",u,v,t);
        if(isset(u,v))continue;
        sum += t;
        unions(u,v);
    }
    printf("%lld",sum);
}