Untitled

import java.util.*;
public class UniqueSubstrings {
    static class Node{
        Node children[] = new Node[26];
        boolean eow = false;

        public Node(){
            for(int i=0;i<children.length;i++){
                children[i] = null;
            }
        }
    }

    public static Node root = new Node();
    public static void insert(String word){
        Node curr = root;
        for(int i=0;i<word.length();i++){
            int idx = word.charAt(i) - 'a';
            if(curr.children[idx]==null){
                curr.children[idx] = new Node();
            }
            curr = curr.children[idx];
        }
        curr.eow = true;
    }
    public static boolean search(String key){
        Node curr = root;
        for(int level = 0; level<key.length();level++){
            int idx = key.charAt(level) - 'a';
            if(curr.children[idx]==null){
                return false;
            }
            curr = curr.children[idx];
        }
        return curr.eow == true;
    }
    public static int countNodes(Node root){
        if(root==null){
            return 0;
        }
        int count = 0;
        for(int i=0;i<26;i++){
            if(root.children[i]!=null){
                count += countNodes(root.children[i]);
            }
        }
        return count+1;
    }
    public static void main(String[] args) {
        String str = "ababa";

        // suffix -> insert -> trie;
        for(int i=0;i<str.length();i++){
            String suffix = str.substring(i);
            insert(suffix);
        }

        System.out.println(countNodes(root));
   }
}