DesignAddandSearchWordsDataStructure

import java.util.*;
import java.util.lang.*;
import java.io.*;

class WordDictionary {

    /** Initialize your data structure here. */
    class TrieNode{
        TrieNode[] children;
        boolean isWord;
        public TrieNode(){
            children=new TrieNode[26];
            isWord=false;
        }
    }
    private TrieNode root;
    
    public WordDictionary() {
        root=new TrieNode();
    
        }
    
    /** Adds a word into the data structure. */
    public void addWord(String word) {
        TrieNode curr=root;
        for(char c : word.toCharArray()){
            int index=(int)(c-'a');
            if(curr.children[index]==null){
                curr.children[index]=new TrieNode();
            }
            curr=curr.children[index];
        }
        curr.isWord=true;
    }
    
    /** Returns if the word is in the data structure. A word could contain the dot character '.' to represent any one letter. */
    public boolean search(String word) {
        return find(word,root,0);
    }
private boolean find(String word,TrieNode curr,int index){
    if(index==word.length()){ return curr.isWord;}
    char c = word.charAt(index);
      if(c=='.'){
          for(int i=0;i<26;i++){
              if(curr.children[i]!=null&&find(word,curr.children[i],index+1))
                  return true;
          }
          return false;
      }
    else{
        return curr.children[c-'a']!=null && find(word,curr.children[c-'a'],index+1);
        
    }
}
}

/**
 * Your WordDictionary object will be instantiated and called as such:
 * WordDictionary obj = new WordDictionary();
 * obj.addWord(word);
 * boolean param_2 = obj.search(word);
 */