题解 | 最长回文子串

s = input()
len_s = len(s)
len_b = 1
for i in range(len_s):
    if i > len_s - len_b:
        break
    for j in range(i + len_b, len_s + 1):
        l = j - i
        if l > len_b:
            h = l // 2
            if s[i : i + h] == s[j - 1 : j - 1 - h : -1]:
                len_b = l
print(len_b)