feat: add swift implementation to lcof2 problem: No.055 (doocs#3084)

klever34 · web-flow · commit 4614207dd08f · 2024-06-10T21:22:20.000+08:00
diff --git a/lcof2/剑指 Offer II 055. 二叉搜索树迭代器/README.md b/lcof2/剑指 Offer II 055. 二叉搜索树迭代器/README.md
@@ -431,6 +431,60 @@ BSTIterator.prototype.hasNext = function () {
  */
 ```
 
+#### Swift
+
+```swift
+/* class TreeNode {
+*     var val: Int
+*     var left: TreeNode?
+*     var right: TreeNode?
+*     init() {
+*         self.val = 0
+*         self.left = nil
+*         self.right = nil
+*     }
+*     init(_ val: Int) {
+*         self.val = val
+*         self.left = nil
+*         self.right = nil
+*     }
+*     init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {
+*         self.val = val
+*         self.left = left
+*         self.right = right
+*     }
+* }
+*/
+
+class BSTIterator {
+    private var cur = 0
+    private var vals = [Int]()
+
+    init(_ root: TreeNode?) {
+        inorder(root)
+    }
+
+    func next() -> Int {
+        let value = vals[cur]
+        cur += 1
+        return value
+    }
+
+    func hasNext() -> Bool {
+        return cur < vals.count
+    }
+
+    private func inorder(_ root: TreeNode?) {
+        guard let node = root else {
+            return
+        }
+        inorder(node.left)
+        vals.append(node.val)
+        inorder(node.right)
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/lcof2/剑指 Offer II 055. 二叉搜索树迭代器/Solution.swift b/lcof2/剑指 Offer II 055. 二叉搜索树迭代器/Solution.swift
@@ -0,0 +1,49 @@
+/* class TreeNode {
+*     var val: Int
+*     var left: TreeNode?
+*     var right: TreeNode?
+*     init() {
+*         self.val = 0
+*         self.left = nil
+*         self.right = nil
+*     }
+*     init(_ val: Int) {
+*         self.val = val
+*         self.left = nil
+*         self.right = nil
+*     }
+*     init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {
+*         self.val = val
+*         self.left = left
+*         self.right = right
+*     }
+* }
+*/
+
+class BSTIterator {
+    private var cur = 0
+    private var vals = [Int]()
+
+    init(_ root: TreeNode?) {
+        inorder(root)
+    }
+
+    func next() -> Int {
+        let value = vals[cur]
+        cur += 1
+        return value
+    }
+
+    func hasNext() -> Bool {
+        return cur < vals.count
+    }
+
+    private func inorder(_ root: TreeNode?) {
+        guard let node = root else {
+            return
+        }
+        inorder(node.left)
+        vals.append(node.val)
+        inorder(node.right)
+    }
+}
