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摘要：最近买了很多数学方面的书，从《天才引导的历程》，《什么是数学》到《费马大定理》，《黎曼猜想漫谈》。基本上是科普性质，但也需要一定的数学知识和耐心才能读进去。 数学跟我的工作没有太多的联系，只是为了探求智力上的极限，似乎这慢慢成为我娱乐的一种方式。在思考当中我找不到比数学问题更能考验纯粹思维能力的东西了。 在数学家的世界里，用几个月甚至数年的时光去搞明白一些问题好像是很平常的事情。即使是具... 阅读全文

摘要：Encode a string by counting the consecutive letter. (i.e., "aaaabbxxxyyz" might become "a4b2x3y2z1"). 分析： 这个问题是一个基本的数据压缩算法，将相邻的字符计数存储。解法没有什么特别需要注意的地方，按部就班的实现代码就可以了。 class Solution: # @param s,... 阅读全文

摘要：Follow up for "Find Minimum in Rotated Sorted Array":What if duplicates are allowed? Would this affect the run-time complexity? How and why? Suppose a sorted array is rotated at some pivot unknown ... 阅读全文

摘要：Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cas... 阅读全文

摘要：Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactl... 阅读全文

摘要：Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target. Note: Elements in a... 阅读全文

摘要：Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. Note: Elements in a triplet (a,b,c) must... 阅读全文

摘要：Given an array of integers, find two numbers such that they add up to a specific target number. The function twoSum should return indices of the two numbers such that they add up to the target, whe... 阅读全文

摘要：Write a function to find the longest common prefix string amongst an array of strings. 分析: 对一组字符串找到最长公共前缀。 因为只是找前缀所以可以以第一个字符串为基础，按个字符与其它字符串比较，直到有字符串已经遍历完或者碰到不一致的字符，返回到当前为止第一个字符串的前缀即可。 class Solution... 阅读全文

摘要：Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). Find the minimum element. You may assume no duplicate exists in the arr... 阅读全文

摘要：读《费马大定理》这本书的时候，第二章一开始引用了一段文字，出自阿瑟•波格斯（Arthur Porges）的《魔王与西蒙•弗拉格》“你听我说，”魔王吐露说，“就连其它星球上最出色的数学家——远远超出你们——也没能解开这个谜！嗨，土星上有个家伙——他看上去像是踩着高跷的蘑菇——能用心算解偏微分方程，就连... 阅读全文