PU Longest Palindromic Substring

char* longestPalindrome(char* s) {
    if (!s || !*s) return 0;
    int i, res = 1, l = 0, r = 0;
    for (i = 1; s[i]; i++) {
        int j;
        for (j = 1; j <= i && s[i + j] && s[i - j] == s[i + j]; j++);
        if (2 * j - 1 > res) {
            l = i - j + 1;
            r = i + j - 1;
            res = 2 * j - 1;
        }
        if (s[i - 1] == s[i]) {
            for (j = 1; i - 1 - j >= 0 && s[i + j] && s[i - 1 - j] == s[i + j]; j++);
            if (2 * j > res) {
                l = i - j;
                r = i + j - 1;
                res = 2 * j;
            }
        }
    }
    char *rs = malloc(r - l + 2);
    memcpy(rs, s + l, r - l + 1);
    rs[r - l + 1] = 0;
    return rs;
}

class Solution(object):
    def longestPalindrome(self, s):
        """
        :type s: str
        :rtype: str
        """
        if len(s) < 2: return s
        l = ['*']
        for c in s: l.extend([c, '*'])
        max_center, max_radius = 1, 1
        center, left = 1, 2
        d = [0] * len(l)
        d[1] = 1
        for cur in range(2, len(l)):
            if 2 * center - cur >= 0:
                radius = d[2 * center - cur]
                if radius + cur < left:
                    d[cur] = radius
                    continue
            radius = left - cur if left > cur else 0
            while cur - radius - 1 > -1 and cur + radius + 1 < len(l) and l[cur - radius - 1] == l[cur + radius + 1]:
                radius += 1
            if cur + radius > left:
                if radius > max_radius:
                    max_center = cur
                    max_radius = radius
                center = cur
                left = cur + radius
            if left == len(l) - 1: break
            d[cur] = radius
        l = l[max_center - max_radius: max_center + max_radius + 1]
        return ''.join([c for c in l if c != '*'])