题解 | #密码截取#

import sys

for line in sys.stdin:
    a = line.strip()
    max_len = 0
    for i in range(0, len(a)):
        left, right = i, i
        while left >= 0 and right < len(a) and a[left] == a[right]:
            left -= 1
            right += 1
        max_len = max(max_len, right-left-1)
        left, right = i, i+1
        while left >= 0 and right < len(a) and a[left] == a[right]:
            left -= 1
            right += 1
        max_len = max(max_len, right-left-1)
    print(max_len)
        

遍历每个元素从中间向两边扩散