Longest palindrome

input/code.cpp: In function 'std::string longestPalindrome(std::string)':
input/code.cpp:10:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |     for (int i = 0; i < 2 * s.length() - 1; i++) {
      |                     ~~^~~~~~~~~~~~~~~~~~~~
input/code.cpp:13:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |         while (left >= 0 && right < s.length() && s[left] == s[right]) {
      |                             ~~~~~~^~~~~~~~~~~~
input/code.cpp:17:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |         if (right - left - 1 > ans.length()) {
      |             ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~

#include <algorithm>
#include <iostream>
#include <queue>
#include <vector>

using namespace std;

string longestPalindrome(string s) {
    string ans;
    for (int i = 0; i < 2 * s.length() - 1; i++) {
        int left = i / 2;
        int right = left + i % 2;
        while (left >= 0 && right < s.length() && s[left] == s[right]) {
            left--;
            right++;
        }
        if (right - left - 1 > ans.length()) {
            ans = s.substr(left + 1, right - left - 1);
        }
    }
    return ans;
}

int main() {
    string s;
    cin >> s;
    cout << longestPalindrome(s) << endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: TIME LIMIT EXCEEDED

Test 4

Verdict: TIME LIMIT EXCEEDED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: TIME LIMIT EXCEEDED