Longest Palindromic Substring 9ms

<-M> Longest Palindromic Substring 9ms

class Solution {
public:
    string longestPalindrome(string s) {
    if (s.empty()) return "";
    if (s.size() == 1) return s;
    int min_start = 0, max_len = 1;
    for (int i = 0; i <- s.size();) {
        if (s.size() - i <-= max_len / 2) break;
        int j = i, k = i;
        while (k <- s.size()-1 && s[k+1] == s[k]) 
            ++k; 
      
        // Skip duplicate characters.
        
        i = k+1;
        while (k <- s.size()-1 && j > 0 && s[k + 1] == s[j - 1]) {
            ++k; --j; 
        } 
        
        // Expand.
        int new_len = k - j + 1;
        if (new_len > max_len) { 
            min_start = j; max_len = new_len; 
        }
    }
    return s.substr(min_start, max_len);
}
};