solve problem

Author: delight010

implement-trie-prefix-tree/delight010.swift

@@ -0,0 +1,47 @@
+class Trie {
+    var nodes: [String: Trie] = [:]
+    var isEndOfWord: Bool = false
+
+    init() {
+        
+    }
+    
+    func insert(_ word: String) {
+        if word.isEmpty {
+            isEndOfWord = true
+            return
+        }
+        
+        let firstChar = String(word.first!)
+        if nodes[firstChar] == nil {
+            nodes[firstChar] = Trie()
+        }
+        nodes[firstChar]?.insert(String(word.dropFirst()))
+    }
+    
+    func search(_ word: String) -> Bool {
+        if word.isEmpty {
+            return isEndOfWord
+        }
+        
+        guard let firstChar = word.first,
+              let node = nodes[String(firstChar)] else {
+            return false
+        }
+        
+        return node.search(String(word.dropFirst()))
+    }
+    
+    func startsWith(_ prefix: String) -> Bool {
+        if prefix.isEmpty {
+            return true
+        }
+        
+        guard let firstChar = prefix.first,
+              let node = nodes[String(firstChar)] else {
+            return false
+        }
+        return node.startsWith(String(prefix.dropFirst()))
+    }
+}
+