solve problem

Author: delight010

design-add-and-search-words-data-structure/delight010.swift

@@ -0,0 +1,58 @@
+class WordDictionary {
+    
+    class TrieNode {
+        var children: [Character: TrieNode] = [:]
+        var isEndOfWord: Bool = false
+    }
+    
+    var root: TrieNode?
+
+    init() {
+        root = TrieNode()
+    }
+    
+    func addWord(_ word: String) {
+        var currentNode = root
+        for (index, char) in word.enumerated() {
+            if currentNode?.children[char] == nil {
+                currentNode?.children[char] = TrieNode()
+            }
+            currentNode = currentNode?.children[char]
+            if index == word.count - 1 {
+                currentNode?.isEndOfWord = true
+            }
+        }
+    }
+    
+    func search(_ word: String) -> Bool {
+        return dfs(root, word: word, index: 0)
+    }
+    
+    func dfs(_ node: TrieNode?, word: String, index: Int) -> Bool {
+        guard let currentNode = node else {
+            return false
+        }
+        if index == word.count {
+            return currentNode.isEndOfWord
+        }
+        
+        let char = Array(word)[index]
+        if char == "." {
+            for child in currentNode.children.values {
+                let result = dfs(child, word: word, index: index + 1)
+                if result {
+                    return true
+                }
+            }
+        } else {
+            if let child = currentNode.children[char] {
+                return dfs(child, word: word, index: index + 1)
+            } else {
+                return false
+            }
+        }
+        
+        return false
+    }
+}
+