【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 1
\ / / / \ 3 2 1 ...
分类：
其他好文 时间：
2014-06-01 15:34:24
阅读次数：
231
【题目】
Given n, generate all structurally unique BST's (binary search trees) that store values 1...n.
For example,
Given n = 3, your program should return all 5 unique BST's shown below.
1 3 3 2 1
\ / / / \ ...
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其他好文 时间：
2014-06-01 15:33:45
阅读次数：
297
问题：
对于给定序列1...n，permutations共有 n！个，那么任意给定k，返回第k个permutation。0
分析：
这个问题要是从最小开始直接到k，估计会超时，受10进制转换为二进制的启发，对于排列，比如 1,2,3 是第一个，那么3！= 6，所以第6个就是3,2,1。也就是说，从开始的最小的序列开始，到最大的序列，就是序列个数的阶乘数。那么在1，3 , 2的时候呢？调整一...
分类：
其他好文 时间：
2014-06-01 14:03:55
阅读次数：
257
Remove ElementGiven an array and a value,
remove all instances of that value in place and return the new length.The order
of elements can be changed. ...
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其他好文 时间：
2014-06-01 12:29:11
阅读次数：
190
Merge Sorted ArrayGiven two sorted integer
arrays A and B, merge B into A as one sorted array.Note: You may assume that A
has enough space (size that ...
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其他好文 时间：
2014-06-01 12:04:32
阅读次数：
175
【题目】
Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.
Below is one possible representation of s1 = "great":
great
/ gr eat
/ \ / g r e at
/ ...
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其他好文 时间：
2014-06-01 09:41:05
阅读次数：
196
【题目】
Given two sorted integer arrays A and B, merge B into A as one sorted array.
Note:
You may assume that A has enough space (size that is greater or equal to m + n) to hold additional elements from B. The number of elements initialized in A and B are...
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其他好文 时间：
2014-06-01 09:21:16
阅读次数：
292
【题目】
The gray code is a binary numeral system where two successive values differ in only one bit.
Given a non-negative integer n representing the total number of bits in the code, print the sequence of gray code. A gray code sequence must begin with 0.
...
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其他好文 时间：
2014-06-01 09:16:29
阅读次数：
242
【题目】
A message containing letters from A-Z is being encoded to numbers using the following mapping:
'A' -> 1
'B' -> 2
...
'Z' -> 26
Given an encoded message containing digits, determine the total number of ways to decode it.
For example,
Given encoded ...
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其他好文 时间：
2014-06-01 08:59:37
阅读次数：
258
【题目】
Given a collection of integers that might contain duplicates, S, return all possible subsets.
Note:
Elements in a subset must be in non-descending order.
The solution set must not contain duplicate subsets.
For example,
If S = [1,2,2], a solution ...
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其他好文 时间：
2014-06-01 08:51:06
阅读次数：
292
