Leetcode 3272. Find the Count of Good Integers

Count how many n-digit integers (no leading zeros) have a digit multiset that can be rearranged into a palindrome divisible by k. The core challenge is to enumerate digit-count multisets that satisfy palindrome parity and no-leading-zero constraints and the divisibility-by-k condition, then sum the number of distinct n-digit permutations for each valid multiset.