完美洗牌 题解

本题很简单，按照题意在”一个确定置换作用下，找字符串的最小周期“这个方向进行模拟即可。

t = int(input())
for i in range(t):
    n = int(input())
    s0 = list(input().strip())
    p = [0] * n
    h = n // 2
    for i in range(n):
        if i < h:
            p[i] = 2 * i
        else:
            p[i] = 2 * (i - h) + 1
    s = s0[:]
    k = 0
    while True:
        t = [0] * n
        for i in range(n):
            t[p[i]] = s[i]
        s = t
        k += 1
        if s == s0:
            print(k)
            break