2050B.cpp

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

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    int t; cin >> t;
    while (t--) {
        int n; cin >> n;
        ll sum1 = 0, sum2 = 0;

        for (int i = 0; i < n; i++) {
            int temp; cin >> temp;
            if (i % 2 == 0)
                sum1 += temp; 
            else
                sum2 += temp; 
        }

        int count1 = (n + 1) / 2; 
        int count2 = n / 2;        

        if ((sum1 / count1 == sum2 / count2) &&
            (sum1 % count1 == 0) && (sum2 % count2 == 0))
            cout << "YES\n";
        else
            cout << "NO\n";
    }

    return 0;
}