My solution to Tries: Contacts Challenge on Hacker Rank

This is my solution to challenge about the “Tries” data structure. Click here to see the challenge.

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;


class Node{
        Node[] children = new Node[26];
        int completeChildren = 0;
}

public class Solution {
    static Node head;

    public static void main(String[] args) {
        head = new Node();
        List searchResults = new ArrayList();
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        for(int a0 = 0; a0 < n; a0++){
            String op = in.next();
            String contact = in.next();
            
            if(op.equals("add")){
                addContact(contact);
            }else if(op.equals("find")){
            	searchResults.add(countOccurances(contact));
            }
        }
        printResult(searchResults);
    }
    
    public static void printResult(List searchResults){
        for(Integer result:searchResults){
            System.out.println(result);
        }
    }
    public static int countOccurances(String term){
        Node currentNode = head;
         for(int i=0; i < term.length();i++){
            char c = term.charAt(i);
            currentNode = currentNode.children[getCode(c)];
            if(currentNode == null ){
                return 0;
            }
        }
        return currentNode.completeChildren;
        
    }
    public static int getCode(char c){
        return c - ((int) 'a');
    }
    public static void addContact(String contact){
        if(contact == ""){
            return;
        }
        Node currentNode = head ;
        for(int i=0; i < contact.length();i++){
            char c = contact.charAt(i);
            currentNode = getOrAddNode(currentNode, c);
        } 
        return;
    }

    
    public static Node getOrAddNode(Node node, char c){
        Node nextChild = node.children[getCode(c)];
        if(nextChild != null){
            nextChild.completeChildren++;
        }else{
            nextChild = new Node();
            nextChild.completeChildren++;
            node.children[getCode(c)]= nextChild;
        }
        return nextChild;
    }
}