Trie contracts problem. Hackerrank

contracts.java

class TrieNode{
    public static int ALPHABET_SIZE = 26;
    TrieNode[] children = new TrieNode[ALPHABET_SIZE];
    int size = 0;
    
    public int charIndex(char c){
        return c - 'a';
    }
    public TrieNode getNode(char c){
        return children[charIndex(c)];
    }
    public void setNode(char c,TrieNode node){
        children[charIndex(c)] = node;
    }
    public void add(String s){
        add(s,0);
    }
    public void add(String s,int index){
        size++;
        if(index == s.length()) return;
        char current = s.charAt(index);
        TrieNode child = getNode(current);
        if(child == null){
            child = new TrieNode();
            setNode(current,child);
        }
        child.add(s,index+1);
    }
    public int findCount(String s,int index){
        if(s.length() == index){
            return size;
        }
        TrieNode child = getNode(s.charAt(index));
        if(child == null) return 0;
        return  child.findCount(s, index+1);
    }
}
public class Solution {

    /*
     * Complete the contacts function below.
     */
    static int[] contacts(String[][] queries) {
        /*
         * Write your code here.
         */
         int [] aux = new int[100001];
         int j = 0;

         TrieNode root = new TrieNode();
         for(int i=0;i<queries.length;i++){
             if(queries[i][0].equals("add")){
                 root.add(queries[i][1]);
             }
             else{
                 int res = root.findCount(queries[i][1],0);
                 aux[j++] = res;
             }
         }
         int [] res = new int[j];
         for(int i=0;i<j;i++){
             res[i] = aux[i];
         }
         return res;

    }