saving words at each node for suggestion

Author: Arjiit

Trie/searchSuggestionSystem.java

@@ -0,0 +1,44 @@
+class Solution {
+    /*  m - avg length of product, n - length of product array
+        Sorting strings array - O(mnlogn)
+        TC - O(mnlogn)
+        Building trie - O(mn)
+        Space - O(mn + Lm) L = length of word search. (as we are constructing L genrated sublists)
+    */
+    class TrieNode {
+        TrieNode[] child;
+        LinkedList<String> suggestion = new LinkedList<>();
+        public TrieNode() {
+            child = new TrieNode[26];
+        }
+    }
+    
+    public void insert(String word, TrieNode root) {
+        TrieNode cur = root;
+        for (int i=0; i<word.length(); i++) {
+            if (cur.child[word.charAt(i) - 'a'] == null) {
+                cur.child[word.charAt(i) - 'a'] = new TrieNode();
+            }
+            cur = cur.child[word.charAt(i) - 'a'];
+            if (cur.suggestion.size() < 3) {
+                cur.suggestion.add(word); // put products with same prefix in the suggestion list
+            }
+        }
+    }
+    public List<List<String>> suggestedProducts(String[] products, String searchWord) {
+        Arrays.sort(products); // sorting products array of strings
+        
+        TrieNode root = new TrieNode();
+        for (String p: products) {
+            insert(p, root);
+        }
+        List<List<String>> res = new ArrayList<>();
+        for (char c: searchWord.toCharArray()) {
+            if (root != null) {
+                root = root.child[c - 'a'];
+            }
+            res.add(root == null ? Arrays.asList(): root.suggestion);
+        }
+       return res; 
+    }
+}