Perfect-subarray

perfect-subarray.cpp

#include<bits/stdc++.h>
#include<iostream>
using namespace std;
#define ll long long
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int n;
    cin >> n;
    vector<ll> a(n);
    unordered_map<ll,ll> m;
    m[0] = 1;
    ll minSum = 0,sum = 0,ans = 0;
    for(ll i = 0; i < n; i++)
    {
        cin >> a[i];
        sum += a[i];

        for(ll j=0;(sum-j*j)>=minSum;++j)
        {
            if(m.count(sum-j*j)==1)
                ans+=m[sum-j*j];
        }
        minSum = min(minSum,sum);
        m[sum]+=1;
    }
    cout<<ans<<"\n";
    
}