1322C - Instant Noodles - CodeForces Solution

#include<bits/stdc++.h>
#define x first
#define y second
#define int long long 
#define pb push_back
using namespace std;
typedef pair<int,int>PII;
const int N=5e5+5,M=1e6+5,INF=998244353;
int n,m,k,pos,cnt,a[N];
set<int>s[N];
int gcd(int a,int b)
{
	return b?gcd(b,a%b):a;
}
void solve()
{
	cin>>n>>m;
	map<set<int>,int>mp;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i]; 
		s[i].clear();
	}
	for(int i=1;i<=m;i++)
	{
		int a,b;
		cin>>a>>b;
		s[b].insert(a);
	}
	int ans=0;
	for(int i=1;i<=n;i++)
	if(s[i].size())mp[s[i]]+=a[i];
	for(auto now:mp)
	{
		if(ans==0)ans=now.y;
		else ans=gcd(ans,now.y);
	}
	cout<<ans<<'\n';
}
signed main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
	int T;cin>>T;
	while(T--)
	solve();
	return 0;
}