题解 | 小红的双生串

from collections import Counter


def double_string(st: str, n: int) -> int:
    if len(set(st)) == 1:  # 代表字符串只由一个字符组成
        return 0
    return n - sorted(list(Counter(st).values()))[-1]


while True:
    try:
        s = input().strip()
        n = len(s)
        s1 = s[0:n // 2]  # 字符串的上半
        s2 = s[n // 2:n]  # 字符串的下半
        print(double_string(s1, n // 2) + double_string(s2, n // 2))
    except:
        break