145. Binary Tree Postorder Traversal #
题目 #
Given a binary tree, return the postorder traversal of its nodes’ values.
Example:
Input: [1,null,2,3]
1
\
2
/
3
Output: [3,2,1]
Follow up: Recursive solution is trivial, could you do it iteratively?
题目大意 #
后根遍历一颗树。
解题思路 #
递归的实现方法，见代码。
代码 #
package leetcode
/**
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
func postorderTraversal(root *TreeNode) []int {
var result []int
postorder(root, &result)
return result
}
func postorder(root *TreeNode, output *[]int) {
if root != nil {
postorder(root.Left, output)
postorder(root.Right, output)
*output = append(*output, root.Val)
}
}