题解 | #最长回文子串#求最长，就从最长开始找

import sys
def f(s):
    for le in range(len(s),1,-1):
        for st in range(0, len(s)-le+1):
            tmp=s[st:st+le]
            if tmp==tmp[::-1]:
                return(le)
    return(1)
for line in sys.stdin:
    l=line.strip()
    print(f(l))

之前的蠢方法，从最小长度开始找：

import sys
def f(s):
    ma=1
    for le in range(2,len(s)+1):
        for st in range(0, len(s)-le+1):
            tmp=s[st:st+le]
            if tmp==tmp[::-1]:
                ma=le
    print(ma)
for line in sys.stdin:
    l=line.strip()
    f(l)