PARITY C++

#include <bits/stdc++.h>
using namespace std;

int n, m;
int a[100005],s[100005];
int d[200005];
int t=100000;

void nhap_va_dem()
{
    cin>>n;
    s[0]=0;d[0+t]=1;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
        if(a[i]%2==0) s[i]=s[i-1]+1;
        else s[i]=s[i-1]-1;
        d[s[i]+t]++;
    }
}

void giai()
{
    int res=0;
    for(int i=0;i<=n;i++)
    {
        res=res+d[s[i]+t]-1;
    }
    cout<<(res/2);
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    freopen("parity.inp", "r", stdin);
    freopen("parity.out", "w", stdout);
    nhap_va_dem();
    giai();
}