1118B - Tanya and Candies - CodeForces Solution

#include <bits/stdc++.h>

#define int long long
#define ll long long
#define ld long double
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
using namespace std;
int inf=1000000000000000007;
int mod=1000000007;
int mod1=998244353;

const bool multi=0;

const int N=200007;

int a[N];
int P[N][2];
int S[N][2];

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int tt;
    if(multi)
        cin>>tt;
    else tt=1;
    while(tt--)
    {
        int n;
        cin>>n;
        for(int i=1;i<=n;i++) cin>>a[i];
        for(int i=1;i<=n;i++)
        {
            P[i][0]=P[i-1][0];
            P[i][1]=P[i-1][1];
            P[i][i%2]+=a[i];
        }
        for(int i=n;i>0;i--)
        {
            S[i][0]=S[i+1][0];
            S[i][1]=S[i+1][1];
            S[i][i%2]+=a[i];
        }
        int ans=0;
        for(int i=1;i<=n;i++)
        {
            int c0=P[i-1][0]+S[i+1][1];
            int c1=P[i-1][1]+S[i+1][0];
            if(c0==c1)
            {
                ans++;
            }
        }
        cout<<ans;
    }


    return 0;
}