Longest palindrome

def longestPalindrome(s):
    n = len(s)
    dp = [[False] * n for _ in range(n)]
    max_len = 1
    start = 0

    for i in range(n):
        dp[i][i] = True

    for i in range(n - 1):
        if s[i] == s[i + 1]:
            dp[i][i + 1] = True
            start = i
            max_len = 2

    for k in range(3, n + 1):
        for i in range(n - k + 1):
            j = i + k - 1

            if dp[i + 1][j - 1] and s[i] == s[j]:
                dp[i][j] = True

                if k > max_len:
                    start = i
                    max_len = k

    return s[start:start + max_len]

s = input()
print(longestPalindrome(s))

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: RUNTIME ERROR

Test 4

Verdict: RUNTIME ERROR

Test 5

Verdict: RUNTIME ERROR

Test 6

Verdict: RUNTIME ERROR

Test 7

Verdict: RUNTIME ERROR

Test 8

Verdict: RUNTIME ERROR

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: RUNTIME ERROR

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: RUNTIME ERROR