feat: add swift implementation to lcof2 problem: No.045 (doocs#3060)

klever34 · web-flow · commit b89c772dc36e · 2024-06-07T17:42:32.000+08:00
diff --git a/lcof2/剑指 Offer II 045. 二叉树最底层最左边的值/README.md b/lcof2/剑指 Offer II 045. 二叉树最底层最左边的值/README.md
@@ -194,6 +194,56 @@ func findBottomLeftValue(root *TreeNode) int {
 }
 ```
 
+#### 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 Solution {
+    func findBottomLeftValue(_ root: TreeNode?) -> Int {
+        var q = [TreeNode]()
+        q.append(root!)
+        var ans = -1
+        while !q.isEmpty {
+            let n = q.count
+            for i in 0..<n {
+                let node = q.removeFirst()
+                if i == 0 {
+                    ans = node.val
+                }
+                if let left = node.left {
+                    q.append(left)
+                }
+                if let right = node.right {
+                    q.append(right)
+                }
+            }
+        }
+        return ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/lcof2/剑指 Offer II 045. 二叉树最底层最左边的值/Solution.swift b/lcof2/剑指 Offer II 045. 二叉树最底层最左边的值/Solution.swift
@@ -0,0 +1,45 @@
+/* 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 Solution {
+    func findBottomLeftValue(_ root: TreeNode?) -> Int {
+        var q = [TreeNode]()
+        q.append(root!)
+        var ans = -1
+        while !q.isEmpty {
+            let n = q.count
+            for i in 0..<n {
+                let node = q.removeFirst()
+                if i == 0 {
+                    ans = node.val
+                }
+                if let left = node.left {
+                    q.append(left)
+                }
+                if let right = node.right {
+                    q.append(right)
+                }
+            }
+        }
+        return ans
+    }
+}
