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