题意:给一棵树,求其先根遍历的结果。思路:(1)深搜法: 1 /** 2 * Definition for a binary tree node. 3 * struct TreeNode { 4 * int val; 5 * TreeNode *left; 6 * ...
public class Solution2 { public List<Integer> preorderTraversal(TreeNode root) { List<Integer> ans = new ArrayList<>(); if (root == null) { return ans; } // 使用栈来辅助实现,Java中用双端队列来代替栈 Deque<TreeNode> stack = new ArrayDeque<>(); stack.addFirst(root); while (!stack...
1#Definition for a binary tree node.2#class TreeNode(object):3#def __init__(self, x):4#self.val = x5#self.left = None6#self.right = None78classSolution(object):9defpreorderTraversal(self, root):10"""11:type root: TreeNode12:rtype: List[int]13"""14ifnotroot:15return[]1617re...
/** * 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> preorderTraversal(TreeNode* root) { vector<int> ret; pre...
* TreeNode(int x) : val(x), left(NULL), right(NULL) {} 8 * }; 9 */ 10 class Solution { 11 public: 12 vector<int> preorderTraversal(TreeNode *root) { 13 vector<int> root_vec; 14 vector<int> left_vec; 15 vector<int>...
importjava.util.ArrayList;importjava.util.List;// 144. Binary Tree Preorder Traversal// https://leetcode.com/problems/binary-tree-preorder-traversal/description/// 二叉树的前序遍历// 时间复杂度: O(n), n为树的节点个数// 空间复杂度: O(h), h为树的高度publicclassSolution{publicclassTreeNod...
非递归前序遍历 代码 # Definition for a binary tree node.# class TreeNode(object):# def __init__(self, x):# self.val = x# self.left = None# self.right = NoneclassSolution(object):defpreorderTraversal(self,root):""" :type root: TreeNode ...
https://leetcode.com/problems/binary-tree-preorder-traversal/description/ 中文版描述 给你二叉树的根节点 root ,返回它节点值的 前序遍历。 示例1: 输入:root = [1,null,2,3] 输出:[1,2,3] 示例2: 输入:root = [] 输出:[] 示例3: 输入:root = [1] 输出:[1] 示例4: 输入:root = [1...
I am implementing Preorder Traversal of Binary Tree (without recursion). The following code runs into an infinite loop. I cannot understand what's happeningvoid Tree::n_preorder() { Node* temp; stack s; cout<<"\nPreorder: "; while(...
packageleetcode// TreeNode definetypeTreeNode=structures.TreeNode/** * Definition for a binary tree node. * type TreeNode struct { * Val int * Left *TreeNode * Right *TreeNode * } */// 解法一 递归funcpreorderTraversal(root*TreeNode)[]int{res:=[]int{}ifroot!=nil{res=append(res,...