feat: add swift implementation to lcof2 problem: No.049 (doocs#3064)

klever34 · web-flow · commit f711e88f3695 · 2024-06-07T17:43:18.000+08:00
diff --git a/lcof2/剑指 Offer II 049. 从根节点到叶节点的路径数字之和/README.md b/lcof2/剑指 Offer II 049. 从根节点到叶节点的路径数字之和/README.md
@@ -189,6 +189,49 @@ func sumNumbers(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 sumNumbers(_ root: TreeNode?) -> Int {
+        return dfs(root, 0)
+    }
+
+    private func dfs(_ root: TreeNode?, _ presum: Int) -> Int {
+        guard let root = root else {
+            return 0
+        }
+        let s = presum * 10 + root.val
+        if root.left == nil && root.right == nil {
+            return s
+        }
+        return dfs(root.left, s) + dfs(root.right, s)
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/lcof2/剑指 Offer II 049. 从根节点到叶节点的路径数字之和/Solution.swift b/lcof2/剑指 Offer II 049. 从根节点到叶节点的路径数字之和/Solution.swift
@@ -0,0 +1,38 @@
+/* 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 sumNumbers(_ root: TreeNode?) -> Int {
+        return dfs(root, 0)
+    }
+
+    private func dfs(_ root: TreeNode?, _ presum: Int) -> Int {
+        guard let root = root else {
+            return 0
+        }
+        let s = presum * 10 + root.val
+        if root.left == nil && root.right == nil {
+            return s
+        }
+        return dfs(root.left, s) + dfs(root.right, s)
+    }
+}
