题解 | 元素方碑

def make_equal(n,a):
    sum_odd = 0
    sum_even = 0
    for j in range(0,n,2):
        sum_odd += a[j]
    for j in range(1,n,2):
        sum_even += a[j]

    if even_or_odd(n):#偶数/奇数
        flag = (sum_odd%(n//2) == 0) and (sum_even%(n//2)==0) and (sum_odd//(n//2) == sum_even//(n//2))   
    else:
        if n == 1:
            flag = 1
        else:
            flag = (sum_odd%((n+1)//2) == 0) and (sum_even%((n-1)//2)==0) and (sum_odd//((n+1)//2) == sum_even//((n-1)//2))

    print("YES"if flag else "NO")



def even_or_odd(n):
    if n%2 ==0:
        return 1
    else:
        return 0



t = int(input())
for i in range(t):
    n = int(input())
    a = list(map(int,input().split()))
    make_equal(n,a)