* TreeNode(int x) : val(x), left(NULL), right(NULL) {} * };*/classSolution {public: vector<int> preorderTraversal(TreeNode*root) { vector<int>ret;if(root ==NULL)returnret; stack<TreeNode*>stk; stk.push(root);while(!stk.empty()) { TreeNode* top =stk.top(); stk.pop(); ret.push_back(top->val);if(t...
Given a binary tree, return the preorder traversal of its nodes' values. Example Given binary tree{1,#,2,3}: 1 \ 2 / 3 return[1,2,3]. SOLUTION 1: 这题首先应该想到递归做法,最简单直观的也是递归做法。首先先来说一下递归是什么,递归其实就是自己调用自己,但是注意的是,递归往往没有返回值。
SOLUTION1&2: 递归及非递归解法: View Code https://github.com/yuzhangcmu/LeetCode_algorithm/blob/master/tree/PreorderTraversal.java
* Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * };*/classSolution {public: vector<int> preorderTraversal(TreeNode*root) { vector<int>result; stack<TreeNode *...
Binary Tree Preorder Traversal 题目链接 题目要求: Given a binary tree, return thepreordertraversal 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?
Note:Recursive solution is trivial, could you do it iteratively? confused what"{1,#,2,3}"means?> read more on how binary tree is serialized on OJ. 思路: preorder用栈两三下就写完了 1vector<int> preorderTraversal(TreeNode *root) {2vector<int>nodes;3if(root == NULL)returnnodes;4stac...
求给定的二叉树的前序遍历。 例如: 给定的二叉树为{1,#,2,3}, 1 2 / 3 返回:[1,2,3] 代码: 1/**2* struct TreeNode {3* int val;4* struct TreeNode *left;5* struct TreeNode *right;6* };7*/89classSolution {10public:11/**12*13* @param root TreeNode类14* @return int整型vec...
6 * TreeNode *right; 7 * TreeNode(int x) : val(x), left(NULL), right(NULL) {} 8 * }; 9 */ 10 class Solution { 11 public: 12 vector<int> preorderTraversal(TreeNode *root) { 13 if(root==NULL) 14 return v; 15 v.push_back(root->val); ...
* TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * };*/classSolution {public: vector<int> preorderTraversal(TreeNode*root) { vector<int>ret_l, ret_r;if( root ){ ret_l= Solution::preorderTraversal(root->left); ...
classSolution {public: vector<int> preorderTraversal(TreeNode*root) {if(!root)return{}; vector<int>res; stack<TreeNode*>s{{root}};while(!s.empty()) { TreeNode*t =s.top(); s.pop(); res.push_back(t->val);if(t->right) s.push(t->right);if(t->left) s.push(t->left); ...