Time: 40 ms (84.14%), Space: 31.7 MB (25.44%) - LeetHub

Author: JanaSabuj

longest-word-in-dictionary/longest-word-in-dictionary.cpp

@@ -0,0 +1,47 @@
+struct TrieNode{
+    bool isEnd;
+    string word;
+    TrieNode* child[26];
+};
+
+void insert(TrieNode* root, string str){
+    TrieNode* curr = root;
+    for(auto c: str){
+        int idx = c - 'a';
+        if(curr->child[idx] == NULL)
+            curr->child[idx] = new TrieNode();
+        curr = curr->child[idx];
+    }
+    
+    curr->isEnd = true;
+    curr->word = str;
+}
+
+void dfs(TrieNode* root, string& res){
+    if(root == NULL)
+        return;
+    
+    if(root->isEnd){
+        res = root->word.size() > res.size() ? root->word : res;              
+    }
+    
+    for(int i = 0; i < 26; i++){
+        if(root->child[i] != NULL and root->child[i]->isEnd)
+            dfs(root->child[i], res);
+    }
+}
+
+class Solution {
+    TrieNode* root;
+public:
+    string longestWord(vector<string>& words) {
+        root = new TrieNode();
+        for(string w: words){
+            insert(root, w);
+        }
+        
+        string res = "";
+        dfs(root, res);
+        return res;
+    }
+};