题目
Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).
For example, this binary tree is symmetric:
1
/ 2 2
/ \ / 3 4 4 3
...
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其他好文 时间：
2014-06-08 18:12:04
阅读次数：
248
题目
Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next level and alternate between).
For example:
G...
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其他好文 时间：
2014-06-08 17:29:07
阅读次数：
315
题目
Given n, how many structurally unique BST's (binary search trees) that store values 1...n?
For example,
Given n = 3, there are a total of 5 unique BST's.
1 3 3 2 ...
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其他好文 时间：
2014-06-08 17:06:58
阅读次数：
235
1. 递归解法
/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
cl...
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其他好文 时间：
2014-06-08 16:51:59
阅读次数：
199
【题目】
Follow up for problem "Populating Next Right Pointers in Each Node".
What if the given tree could be any binary tree? Would your previous solution still work?
Note:
You may only use constant extra space.
For example,
Given the following binary tre...
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其他好文 时间：
2014-06-08 15:46:22
阅读次数：
303
题目
Two elements of a binary search tree (BST) are swapped by mistake.
Recover the tree without changing its structure.
Note:
A solution using O(n)
space is pretty straight forward. Cou...
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其他好文 时间：
2014-06-08 15:32:45
阅读次数：
245
1. 递归解法
2. 非递归解法（空间复杂度O(n)和O(1))...
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其他好文 时间：
2014-06-08 10:47:37
阅读次数：
139
题目
Given a binary tree, find its maximum depth.
The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
方法
使用DFS对树进行遍...
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其他好文 时间：
2014-06-08 10:26:33
阅读次数：
207
题目
Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root).
For example:
Given binary tree {3,9,20...
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其他好文 时间：
2014-06-08 09:23:34
阅读次数：
230
