Test Case Passing: 10/632

blog_llama_4_maverick_coding_lc_question_response.cpp

class Solution {
public:
    string largestPalindrome(int n, int k) {
        string maxNum(n, '9');
        string result = "";

        // Iterate from max possible number to min possible number
        for (long long num = stol(maxNum); num >= stol(string(n, '1') + (n > 1 ? "0" : ""); num--) {
            string strNum = to_string(num);

            // Check if number is palindrome and divisible by k
            if (isPalindrome(strNum) && num % k == 0) {
                result = strNum;
                break;
            }
        }

        return result;
    }

    // Helper function to check if a number is palindrome
    bool isPalindrome(const string& str) {
        int left = 0, right = str.size() - 1;

        while (left < right) {
            if (str[left] != str[right]) {
                return false;
            }
            left++;
            right--;
        }

        return true;
    }
};

Problem Link: https://leetcode.com/problems/find-the-largest-palindrome-divisible-by-k/