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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 messag 阅读全文
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Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.) You have 阅读全文
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Given two binary strings, return their sum (also a binary string). For example, a = "11" b = "1" Return "100". 思路： 模拟加法时候的情形，从最后一位开始进行相加，注意进位的情况。 阅读全文
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转载：https://aitanlu.com/ubuntu-shadowsocks-ke-hu-duan-pei-zhi.html 之前介绍过用搬瓦工的vps（搬瓦工不用vpn已经打不开了）轻松的搭建shadowsocks服务，也可以参考linux-ubuntu下搭建shadowsocks，然后在w 阅读全文
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Given an array of integers, every element appears three times except for one, which appears exactly once. Find that single one. Note:Your algorithm sh 阅读全文
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The set [1,2,3,…,n] contains a total of n! unique permutations. By listing and labeling all of the permutations in order, We get the following sequenc 阅读全文
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Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maxim 阅读全文
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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 whic 阅读全文
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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 阅读全文
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Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example, [1,1,2] have the following unique p 阅读全文