* 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(); ...
01 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第135题(顺位题号是589)。给定一个n-ary树,返回其节点值的前序遍历。例如,给定一个3-ary树: 1 / | \ 3 2 4 / \ 5 6 其前序遍历结果为:[1,3,5,6,2,4]。 本次解题使用的开发工具是eclipse,jdk使用的版本是1.8,环境是win7 64位系统,使...
LeetCode题解之N-ary Tree Preorder Traversal 1、题目描述 2、问题分析 采用递归方法是标准解法。 3、代码 1vector<int> preorder(Node*root) {2vector<int>v;3preNorder(root, v);4returnv;5}67voidpreNorder(Node *root , vector<int> &v)8{9if(root ==NULL)10return;11v.push_back(root->val...
Note: Recursive solution is trivial, could you do it iteratively? SOLUTION1&2: 递归及非递归解法: View Code https://github.com/yuzhangcmu/LeetCode_algorithm/blob/master/tree/PreorderTraversal.java
1classSolution {2public:3vector<int> preorderTraversal(TreeNode*root) {4vector<int>ret;5if(root == NULL)returnret;6stack<TreeNode*>treeStk;7treeStk.push(root);8TreeNode *tmpNode;9while(!treeStk.empty()){10tmpNode =treeStk.top();11treeStk.pop();12ret.push_back(tmpNode->val);13...
Given a binary tree, return the preorder traversal of its nodes' values. Example: Input: [1, null, 1,2,3 ] 1 \ 2 / 3 Output: [1,2,3] Follow up: Recursive solution is trivial, could you do it iteratively? 思路 二叉树的前序遍历方法分为递归法和使用循环辅助栈的方法,递归方法我们在...
【leetcode】589. N-ary Tree Preorder Traversal 题目如下: 解题思路:凑数题+1,话说我这个也是凑数博? 代码如下: classSolution(object):defpreorder(self, root):""":type root: Node :rtype: List[int]"""ifroot ==None:return[] res=[]
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]. 解法一:用栈实现(递归本质) 1/**2* Definition for a binary tree node.3* struct TreeNode {4* int val;5* TreeNode *left;6* TreeNode *...
2、先序方式遍历左子树。 3、先序遍历右子树。 简称:根左右 以下图为例进行先序遍历: image.png 遍历过程如下: [A,A left,A right] -->[A,B,B left, B right,C,C left,C right] --->[A,B,D,E,C,F,F left,G] -->[A,B,D,E,C,F,H,G] ...
Note:Recursive solution is trivial, could you do it iteratively? 2. 题意 先序遍历二叉树,递归的思路是普通的,能否用迭代呢? 3. 思路 非递归思路:<借助stack> vector<int> preorderTraversal(TreeNode *root) { stack<TreeNode* >st; vector<int>vi; ...