leetcode - Binary Tree Postorder Traversal

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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, could you do it iteratively?

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; *///BinTree的後序遍曆struct TreeNode{int val;TreeNode *left;TreeNode *right;TreeNode(int x) : val(x),left(NULL),right(NULL) {}};class Solution {public:std::vector<int> postorderTraversal(TreeNode *root) {std::vector<int> vec;BinTree(root,vec);return vec;    }void BinTree(TreeNode *root,std::vector<int> &vec){if(root != NULL){BinTree(root->left,vec);BinTree(root->right,vec);vec.push_back(root->val);}}private:std::vector<int> vec;};

leetcode - Binary Tree Postorder Traversal