“Java solution for LeetCode 3343: Balanced Permutations with DFS & Memo”

LeetCode3343_BalancedPermutations.java

import java.util.*;

class Solution {
    private static final int MOD = 1_000_000_007;
    private int n;
    private int[] nums;
    private long[][][] memo;
    private long totalPermInv;

    public int countBalancedPermutations(String num) {
        // … your implementation …
    }

    private long dfs(int idx, int evenLeft, int oddLeft, int remSum) {
        // … DFS + memoization …
    }

    private long computeDuplicatesFactorial(int[] A) {
        // … factorial of duplicates …
    }

    private long modInverse(long a) {
        // … Fermat’s little theorem …
    }
}