题解 | 小红的双生串

import sys
from collections import Counter

s = list(sys.stdin.readline().strip())
n = len(s)

left = Counter(s[:n//2])
right = Counter(s[n//2:])

# 前半部分和后半部分需要是相同的，那就遍历 26 * 26 个字符组合，每次遍历一次字符数组修改

min_change = float('inf')
# 遍历
for c1 in range(26):
    for c2 in range(26):
        change = n - left[chr(ord('a') + c1)] - right[chr(ord('a') + c2)]
        if change < min_change:
            min_change = change

print(min_change)