import sys
input = sys.stdin.readline

T=int(input())

for tests in range(T):
    N=int(input())
    A=list(map(int,input().split()))


    flag=1
    for i in range(0,len(A),5):
        if A[i]==A[i+2] and A[i]!=A[i+1] and A[i+1]==A[i+3]==A[i+4]:
            pass
        else:
            flag=0

    if flag==1:
        print("Yes")
    else:
        print("No")