Longest Palindromic Substring（最长回文子串）

string findLongestPalindrome(string & str){
    size_t n = str.size();
    size_t max_length = 0;
    size_t len = 0;
    size_t start = 0;
    if(n <= 1){
        return str;
    }
    
    for(size_t i = 0; i < n; ++i){ //start number
        for(size_t j = i + 1; j < n; ++j){ // end number
            
            size_t temp_i = 0, temp_j = 0;

            for(temp_i = i, temp_j = j; temp_i < temp_j; ++temp_i, --temp_j){
                if(str[temp_i] != str[temp_j]){ // if the corresponding chars are not same. begin next ++j
                    break;
                }
                if((j - i)%2 == 0){ //odd number aaaaa
                    if(temp_j - temp_i <= 2){
                        cout <<i << "->" << j <<'\n';
                        
                        len = j - i + 1;
                        
                        if(len > max_length){
                            max_length  = len;
                            start = i;
                        }

                    }
                }else{
                    if(temp_j - temp_i <= 1){ //even number abba
                        cout <<i << "-->" << j <<'\n';
                        
                        len = j - i + 1;
                        
                        if(len > max_length){ // only when current len is begger than last max_length
                            max_length  = len;
                            start = i;
                        }
                    }
                }
            }
        }
    }
    
    if(max_length > 0){
        return str.substr(start, max_length);
    }
    return "";
}

普通算法，不过这个算法leetcode上超时了。