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| import Foundation
extension MyTreeNodeSolution {
//递归
func inOrderTraversal(_ root: TreeNode?,_ n: inout [Int]) {
if root == nil {
return
}
inOrderTraversal(root?.left, &n)
n.append(root!.val)
inOrderTraversal(root?.right, &n)
}
//非递归
func inOrderTraversal2(_ root: TreeNode?) -> [Int] {
var node = root
var stack = [TreeNode?]()
var res = [Int]()
while !stack.isEmpty || node != nil {
if node != nil {
stack.append(node)
node = node?.left
}else {
node = stack.removeLast()
res.append(node!.val)
node = node?.right
}
}
return res
}
}
|
算法思想：中序遍历：左子树—> 根结点 —> 右子树
github地址：https://github.com/cubegao/LeetCode
