Leetcode 5. Longest Palindromic Substring

class Solution {
public:
    string longestPalindrome(string s) {
        if(s.length()<2) return s;
        int i,left,right,maxlen=0,tleft;
        for(i=0;i<s.length();){
            if(s.length()-i<=maxlen/2) break;
            left=right=i;
            while(right<s.length()-1&&s[right+1]==s[right]) right++;
            i=right+1;
            while(left>0&&right<s.length()-1&&s[left-1]==s[right+1]){left--;right++;}
            if(right-left+1>maxlen){
               maxlen=right-left+1;
               tleft=left;
            }
        }
        return s.substr(tleft,maxlen);
    }
};