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sonjh1217.swift
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41 lines (36 loc) · 1.08 KB
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/**
* Definition for a binary tree node.
* public class TreeNode {
* public var val: Int
* public var left: TreeNode?
* public var right: TreeNode?
* public init() { self.val = 0; self.left = nil; self.right = nil; }
* public init(_ val: Int) { self.val = val; self.left = nil; self.right = nil; }
* public init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {
* self.val = val
* self.left = left
* self.right = right
* }
* }
*/
class Solution {
func invertTree(_ root: TreeNode?) -> TreeNode? {
guard var invertedRoot = root else {
return nil
}
func invert(node: TreeNode?) -> TreeNode? {
guard var node = node else {
return nil
}
if node.left == nil
&& node.right == nil {
return node
}
let left = node.left
node.left = invert(node: node.right)
node.right = invert(node: left)
return node
}
return invert(node: invertedRoot)
}
}