[479. Largest Palindrome Product] #leetcode

478_0913.java

class Solution {
    // O(n^2) O(1)
    public int largestPalindrome(int n) {
        if (n == 1) return 9;
        int max = (int) Math.pow(10, n) - 1;
        for (int v = max-1; v > max/10; v--) {
            long u=Long.valueOf(v+new StringBuilder().append(v).reverse().toString());
            for (long x = max; x*x > u; x--) {
                if (u % x == 0) return (int) (u%1337);
            }
        }
        return 0;
    }
}