Most frequently asked interview question #6 with solution

Longest palindrome substring

Solution in C++:


    string longestPalindrome(string s) {
            int low = 0;
            int high = 0;
            int start = 0;
            int max   = 1;
            int len   = s.length();
        for(int iter = 1; iter < len; ++iter){
           
            //If the palindrome string is of type even aabbaa
            low = iter - 1;
            high = iter;
            while((low >= 0) && (high < len) && (s[low] == s[high])){
                if((high - low + 1) > max){
                    start = low;
                    max   = high - low + 1;
                }
                --low;
                ++high;
            }
           
            low = iter - 1;
            high = iter + 1;
            while((low >= 0) && (high < len) && (s[low] == s[high])){
                if((high - low + 1) > max){
                    start = low;
                    max   = high - low + 1;
                }
                --low;
                ++high;
            }
        }
        string res;

           for(int iter = start; iter < start + max; ++iter){
                res.push_back(s[iter]);
            }

       
        return res;
    }