原题地址:http://oj.leetcode.com/problems/binary-tree-preorder-traversal/ 题意:这题用递归比较简单.应该考察的是使用非递归实现二叉树的先序遍历.先序遍历的遍历顺序是:根,左子树,右子树. 解题思路:如果树为下图: 1 /     \ 2         3 /     \    /    \ 4       5  6     7 使用一个栈.步骤为: 一,先遍历节点1,并入栈,如果有左孩子,继续遍历并入栈,一直到栈为{1,2,4}.…

Binary Tree Preorder Traversal Given a binary tree, return the preorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3},   1    \     2    /   3return [1,2,3]. Note: Recursive solution is trivial, could you do it iteratively?…

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? 一般我们提到树的遍历,最常见的有先序遍历,中序遍历,后序遍历和层序遍历,它们用递归实现起…

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? 这题简单,属于课本习题的难度,题目提示说用迭代试试,当然用递归也可以AC的.迭代的时候要…

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? 中文:二叉树的前序遍历(根-左-右). 能用非递归实现吗? 递归: public cl…

题意:给一棵树,求其先根遍历的结果. 思路: (1)深搜法: /** * 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> preorderT…

# Definition for a binary tree node. # class TreeNode(object): # def __init__(self, x): # self.val = x # self.left = None # self.right = None class Solution(object): def postorderTraversal(self, root): """ :type root: TreeNode :rtype: List[…

# Definition for a binary tree node. # class TreeNode(object): # def __init__(self, x): # self.val = x # self.left = None # self.right = None class Solution(object): def inorderTraversal(self, root): """ :type root: TreeNode :rtype: List[in…

144. Binary Tree Preorder Traversal Difficulty: Medium 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 it…

144. 二叉树的前序遍历 144. Binary Tree Preorder Traversal 题目描述 给定一个二叉树,返回它的 前序 遍历. LeetCode144. Binary Tree Preorder Traversal 示例: 输入: [1,null,2,3] 1 \ 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? Java 实现 Iterative Solution import java.util.LinkedList; import…