From a6c49c4ebe074b1702711b32d6347591258729ee Mon Sep 17 00:00:00 2001
From: thepremshankarsingh
 <146573212+thepremshankarsingh@users.noreply.github.com>
Date: Sun, 8 Oct 2023 17:05:07 +0530
Subject: [PATCH] Create concatinate_word_problem.java (#93)

* Create concatinate_word_problem.java

Hacktober'23
Added a trie problem

* Update concatinate_word_problem.java

Problem link added as comment in the file
---
 Trie/concatinate_word_problem.java | 51 ++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 Trie/concatinate_word_problem.java

diff --git a/Trie/concatinate_word_problem.java b/Trie/concatinate_word_problem.java
new file mode 100644
index 0000000..072f7b3
--- /dev/null
+++ b/Trie/concatinate_word_problem.java
@@ -0,0 +1,51 @@
+//Problem Link: https://leetcode.com/problems/concatenated-words/description/
+package Trie;
+
+class concatinate_word_problem {
+    class Trie{
+        Trie[] children;
+        boolean isWord;
+
+        public Trie(){
+            children = new Trie[26];
+            isWord = false;
+        }
+    }
+    Trie root = new Trie();
+
+    private void buildTrie(String word){
+        Trie trie = root;
+        
+        for(char c : word.toCharArray()){
+            if(trie.children[c-'a'] == null){
+                trie.children[c-'a'] = new Trie();
+            }
+            trie = trie.children[c-'a'];
+        }
+        trie.isWord = true;
+    }
+
+    private boolean searchWord(String words, int count){
+        Trie node = root;
+        for(int i=0; i< words.length(); i++){
+            char c = words.charAt(i);
+            if(node.children[c-'a'] == null) return false;
+            node = node.children[c-'a'];
+            if(node.isWord && searchWord(words.substring(i+1),count+1)) return true;
+        }
+        count++;
+        return (count >1 && node.isWord) ? true : false;
+    }
+    public List<String> findAllConcatenatedWordsInADict(String[] words) {
+        Arrays.sort(words, (a,b)-> a.length()-b.length());
+        ArrayList<String> result = new ArrayList<>();
+
+        for(String word : words){
+            if(searchWord(word, 0)){
+                result.add(word);
+            }
+            else buildTrie(word);
+        }
+        return result;
+    }
+}