题解 | 元素方碑

import java.util.Scanner;
 
public class Main{
    static Scanner in = new Scanner(System.in);
 
    public static void solve(){
        int n = in.nextInt();
        long sum1 = 0, sum2 = 0;
        for(int i = 1; i <= n; i++){
            int x = in.nextInt();
            if(i % 2 == 1) sum1 += x;
            else sum2 += x;
        }
        int a = n/2 + n%2;
        int b = n/2;
        if(b == 0) System.out.println("YES");
        else if(sum1 % a == 0 && sum2 % b == 0 && sum1 / a == sum2 / b) System.out.println("YES");
        else System.out.println("NO");
    }
 
    public static void main(String[] args){
        int t = in.nextInt();
        while(t-- > 0) solve();
    }
}