# [LeetCode] Binary Tree Postorder Traversal, leetcodepostorder

Source: Internet
Author: User

[LeetCode] Binary Tree Postorder Traversal, leetcodepostorder
[Question]

Given a binary tree, return the postorder traversal of its nodes 'values.

For example:
Given binary tree`{1,#,2,3}`,

`   1    \     2    /   3`

Return`[3,2,1]`.

Note: Recursive solution is trivial, cocould you do it iteratively?
[Code]

`/********************************** Date: question: Binary Tree Postorder Traversal * Source: https://oj.leetcode.com/problems/binary-tree-postorder-traversal/* result: AC * Source: LeetCode * conclusion: * *********************************/# include <iostream> # include <malloc. h >#include <vector >#include <stack> using namespace std; struct TreeNode {int val; TreeNode * left; TreeNode * right; TreeNode (int x): val (X), left (NULL), right (NULL) {}}; class Solution {public: vector <int> postorderTraversal (TreeNode * root) {vector <int> v; stack <TreeNode *> stack; TreeNode * p = root; TreeNode * q; do {// traverse the left subtree while (p! = NULL) {stack. push (p); p = p-> left;} q = NULL; while (! Stack. empty () {p = stack. top (); stack. pop (); // whether the right subtree is null or if (p-> right = q) {v. push_back (p-> val); // retained the accessed node q = p;} else {// the current node cannot be accessed, and the p node re-enters the stack. push (p); // process the right subtree p = p-> right; break;} // if} // while} while (! Stack. empty (); // while return v ;}}; // create a binary tree int CreateBTree (TreeNode * & T) {char data; // enter the value of the node in the binary tree in the First Order (one character). '#' indicates the empty tree cin> data; if (data = '#') {T = NULL;} else {T = (TreeNode *) malloc (sizeof (TreeNode); // generate the root node T-> val = data-'0 '; // construct the left subtree CreateBTree (T-> left); // construct the right subtree CreateBTree (T-> right);} return 0;} int main () {Solution solution; treeNode * root (0); CreateBTree (root); vector <int> v = solution. postorderTraversal (root); for (int I = 0; I <v. size (); I ++) {cout <v [I] <endl ;}}`

Related Keywords:

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

## A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

• #### Sales Support

1 on 1 presale consultation

• #### After-Sales Support

24/7 Technical Support 6 Free Tickets per Quarter Faster Response

• Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.