HackerEarth Modify Sequence problem solution

In this HackerEarth Modify Sequence problem solution Suppose we have a sequence of non-negative integers, Namely a_1, a_2, ... ,a_n. At each time we can choose one term a_i with 0 < i < n and we subtract 1 from both a_i and a_i+1. We wonder whether we can get a sequence of all zeros after several operations.

HackerEarth Modify Sequence problem solution.

#include <iostream>
using namespace std;

int main() 
{

    int n,s1=0,s2=0;
    cin>>n;
    int a[n];

    for(int i=0;i<n;i++)

    {
       cin>>a[i];
    }

    for(int i=0;i<n;i++)

    {
        if (i%2==0)

        {
            s1=s1+a[i];
        }

        else

        {
            s2=s2+a[i];
        }

    }

     if (s1==s2)

    {
       cout<<"YES";
    }
    else
    {
       cout<<"NO";
    }

}