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]. 二叉树的前序遍历,根节点→左子树→右子树 解题思路一: 递归实现,JAVA实现如下: 1 2 3 4 5 6 7 8 9 publicList<Integer> preorderTraversal(Tr...
/*** Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * }*/publicclassSolution {publicList<Integer>preorderTraversal(TreeNode root) { Deque<TreeNode> queue =newArrayDeque<TreeNode>(); Lis...
classSolution {public: vector<int> preorderTraversal(TreeNode *root) { vector<int>res; stack<TreeNode *>s;if(root == NULL){//空树returnres; } s.push(root);//放树根while(!s.empty()){ TreeNode*cc =(); s.pop(); res.push_back(cc->val);//访问根if(cc->right !=NULL){ s.p...
class Solution(object): def _preorderTraversal(self, root, result): if root: result.append(root.val) self._preorderTraversal(root.left, result) self._preorderTraversal(root.right, result) def preorderTraversal(self, root): """ :type root: TreeNode :rtype: List[int] """ if root ==...
My code: importjava.util.ArrayList;importjava.util.List;/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */publicclassSolution{public List<Integer>preorderTraversal(TreeNode root...
Given therootof a binary tree, returnthe preorder traversal of its nodes' values. Example 1: image <pre>Input:root = [1,null,2,3] Output:[1,2,3] </pre> Example 2: <pre>Input:root = [] Output:[] </pre> Example 3:
Binary tree traversal: Preorder, Inorder, and Postorder In order to illustrate few of the binary tree traversals, let us consider the below binary tree: Preorder traversal: To traverse a binary tree in Preorder, following operations are carried-out (i) Visit the root, (ii) Traverse the le...
tree-crawl Agnostic tree traversal library. ngryman •1.2.2•9 months ago•20dependents•MITpublished version1.2.2,9 months ago20dependentslicensed under $MIT 58,786 obj-walker Walk or map over objects in a depth-first preorder or postorder manner. ...
每天一算:Binary Tree Preorder Traversal 程序员吴师兄 + 关注 预计阅读时间2分钟 6 年前 LeetCode上第144 号问题:二叉树的前序遍历 题目 给定一个二叉树,返回它的 前序 遍历。 示例: 输入: [1,null,2,3] 输出: [1,2,3] 进阶: 递归算法很简单,你可以通过迭代算法完成吗? 解题思路 用栈(Stack)...
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]. 解题思路: 这个问题最简单的方法是使用递归,但是题目规定不能使用,得使用迭代的方法。 那么我们考虑使用栈来实现。