Solution Design Add and Search Words Data Structure

Author: doitduri

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

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+class WordDictionary {
+    class TrieNode {
+        var children: [Character: TrieNode] = [:]
+        var isEndOfWord: Bool = false
+    }
+    
+    private let root: TrieNode
+    
+    init() {
+        root = TrieNode()
+    }
+    
+    func addWord(_ word: String) {
+        let key = word.lowercased()
+        var current = root
+        
+        for char in key {
+            if current.children[char] == nil {
+                current.children[char] = TrieNode()
+            }
+            
+            if let node = current.children[char] {
+                current = node
+            }
+        }
+        
+        current.isEndOfWord = true
+    }
+    
+    func search(_ word: String) -> Bool {
+        let key = word.lowercased()
+        return searchInNode(Array(key), 0, root)
+    }
+    
+    private func searchInNode(_ word: [Character], _ index: Int, _ node: TrieNode) -> Bool {
+        if index == word.count {
+            return node.isEndOfWord
+        }
+        
+        let currentChar = word[index]
+        
+        if currentChar == "." {
+            for (_, childNode) in node.children {
+                if searchInNode(word, index + 1, childNode) {
+                    return true
+                }
+            }
+            return false
+        } else {
+            guard let nextNode = node.children[currentChar] else {
+                return false
+            }
+            
+            return searchInNode(word, index + 1, nextNode)
+        }
+    }
+}