F9poa9 - Online C++ Compiler & Debugging Tool

#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;

int main() {

    ll n;
    cin>>n;
    ll arr[n+1]={0};
    for(ll i=1;i<=n;i++){
        cin>>arr[i];
    }

    ll x,y;
    cin>>x>>y;

    ll pref[n+1]={0};
    for(ll i=1;i<=n;i++){
        if(i-y>=1){
            pref[i] = arr[i] + pref[i-y];
        }
        else{
            pref[i] = arr[i];
        }
    }

    ll ans = 1e18 ;
    for(ll i=1;i<=n;i++){

        ll check1 = i - (x-1)*y;
        if(check1>=1){
            ll g = pref[i] ;
            if(check1-y>=1){
                g = g - pref[check1-y] ;
            }
            ans = min(g,ans);
            cout<<g ;
            cout<<'\n';
        }
    }
    cout<<ans;


    return 0 ;
}