Find the largest palindrome made from the product of two n-digit numbers.

Since the result could be very large, you should return the largest palindrome mod 1337.

Example:

Input: 2

Output: 987

Explanation: 99 x 91 = 9009, 9009 % 1337 = 987

Note:

The range of n is [1,8].

https://leetcode.com/problems/largest-palindrome-product/discuss/96306/Java-solutions-with-two-different-approaches

class Solution {
    public int largestPalindrome(int n) {
    long max = (long)Math.pow(10, n) - 1;
    long min = max / 10;

    for (long h = max; h > min; h--) {
        long left = h, right = 0;
        for (long i = h; i != 0; right = right * 10 + i % 10, i /= 10, left *= 10);
        long palindrom = left + right;      // construct the palindrome

        for (long i = max; i > min; i--) {
            long j = palindrom / i;
            if (j > i) break;     // terminate if the other number is greater than current number
            if (palindrom % i == 0) return (int)(palindrom % 1337); // found if current number is a factor
        }
    }

    return 9;    // account for case n = 1
}
}