题解 | 小红的ABC

看题，题目要求是求最短的回文子串：只有2或3两种可能
import re
import sys

def solve():
    s = str(input())
    n = len(s)
    for i in range(n - 1):
        if s[i] == s[i+1]:
            print(2)
            return
    for i in range(n - 2):
        if s[i] == s[i + 2]:
            print(3)
            return
    print(-1)

solve()