Given a binary tree, return the preorder traversal of its nodes‘ values.
For example:
Given binary tree {1,#,2,3},
1
2
/
3
return [1,2,3].
Note: Recursive solution is trivial, could you do it iteratively?
本题是非递归先序遍历二叉树，任何一本数据结构书上都有
vector<int> preorderTraversal(TreeNode * root){ vector<int> res; if(root == NULL) return res; stack<TreeNode *> record; record.push(root); while(!record.empty()){ TreeNode *node = record.top(); record.pop(); res.push_back(node->val); if(node->right) record.push(node->right); if(node->left) record.push(node->left); } return res; }
Leetcode Binary Tree Preorder Traversal,布布扣,bubuko.com
Leetcode Binary Tree Preorder Traversal
原文：http://www.cnblogs.com/xiongqiangcs/p/3795492.html