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BinaryTreePostOrderTraversal.cpp
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BinaryTreePostOrderTraversal.cpp
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/*
145. Binary Tree Postorder Traversal
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?
From <https://leetcode.com/problems/binary-tree-postorder-traversal/description/>
*/
/**
* Definition for a binary tree node.
* 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) {
stack<TreeNode*> myStack;
vector<int> result;
if(root == NULL) {
return result;
}
myStack.push(root);
while(!myStack.empty()) {
auto temp = myStack.top(); myStack.pop();
//remember to add in the front
result.insert(result.begin(),temp->val);
if(temp->left != NULL) {
myStack.push(temp->left);
}
if(temp->right != NULL) {
myStack.push(temp->right);
}
}
return result;
}
};