Count anagram that starts with consonant and has no consecutive vowels

AnagramWithAlternateVowel_3.java

package com.example;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

public class AnagramWithAlternateVowel_3 {
    private final int mod = 1000000007;
    private HashMap<Integer, Integer> factMap;

    private void computeFactorial(int n) {
        factMap = new HashMap<>();
        int result = 1;
        factMap.put(0, 1);
        factMap.put(1, 1);
        for (int i = 2; i <= n; i++) {
            result = (result * i) % mod;
            factMap.put(i, result);
        }
    }

    private boolean isVowel(char c) {
        return Arrays.asList('A', 'E', 'I', 'O', 'U').contains(c);
    }

    public int getCount(String s) {
        int len = s.length();
        computeFactorial(len);
        int cCount = 0, vCount = 0;
        HashMap<Character, Integer> cMap = new HashMap<>();
        HashMap<Character, Integer> vMap = new HashMap<>();
        for (int i = 0; i < len; i++) {
            char c = s.charAt(i);
            if (isVowel(c)) {
                vCount++;
                vMap.put(c, vMap.getOrDefault(c, 0) + 1);
            } else {
                cCount++;
                cMap.put(c, cMap.getOrDefault(c, 0) + 1);
            }
        }

        if (cCount != vCount && cCount != vCount + 1) {
            return 0;
        }

        // Permutation of all consonants = cCount!/(cCount - cCountToBeUsed)! => cCount!
        // Duplicate of consonants cCountOfMoreThanOne!
        // Total possible permutation for consonants = cCount!/ cCountOfMoreThanOne!

        int cCountOfMoreThanOne = 1;
        for(Map.Entry<Character, Integer> entry: cMap.entrySet()) {
            if (entry.getValue() > 1) {
                cCountOfMoreThanOne = (cCountOfMoreThanOne * factMap.get(entry.getValue())) % mod;
            }
        }
        int cTotal = factMap.get(cCount) / cCountOfMoreThanOne;

        // Permutation of all vowels = vCount!/(vCount - vCountToBeUsed)! => vCount!
        // Duplicate of vowel vCountOfMoreThanOne!
        // Total possible permutation for vowel = vCount!/ vCountOfMoreThanOne!

        int vCountOfMoreThanOne = 1;
        for(Map.Entry<Character, Integer> entry: vMap.entrySet()) {
            if (entry.getValue() > 1) {
                vCountOfMoreThanOne = (vCountOfMoreThanOne * factMap.get(entry.getValue())) % mod;
            }
        }
        int vTotal = factMap.get(vCount) / vCountOfMoreThanOne;

        // Multiply these two to get final permutation for both consonants and vowel permutation
        return (cTotal * vTotal) % mod;

    }

    public static void main(String[] args) {
        int res = new AnagramWithAlternateVowel_3().getCount("GADO");
        System.out.println(res);

        res = new AnagramWithAlternateVowel_3().getCount("AABCY");
        System.out.println(res);

        res = new AnagramWithAlternateVowel_3().getCount("XAABCY");
        System.out.println(res);
    }
}