题解 | #最长回文子串#

另辟蹊径

while 1:
    try:
        str = input().strip()
        max = 0
        n = len(str)
        if n == 0:
            print(0)
        else:
            for i in range(n-1):
                if str[i] == str[i+1]:
                    for a in range(n-i-1):
                        if str[i-a] != str[i+1+a]:
                            # print(1,i,a)
                            if max < 2*a:
                                max=2*a
                            break
                        elif (i - a == 0 and str[i - a] == str[i + 1 + a]):
                            # print(1, i, a)
                            if max < 2 * a +2:
                                max = 2 * a +2
                            break
                if i < n-2 and str[i] == str[i+2]:
                    for a in range(n-i-2):
                        if str[i-a] != str[i+2+a]:
                            # print(2, i, a)
                            if max < 2*a+1:
                                max = 2*a+1
                            break
                        elif (i - a == 0 and str[i - a] == str[i + 2 + a]):
                            # print(2, i, a)
                            if max < 2 * a + 3:
                                max = 2 * a + 3
                            break
        print(max)
    except:
        break