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题目： You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can yo 阅读全文
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题目： Given two binary strings, return their sum (also a binary string). （Easy） For example,a = "11"b = "1"Return "100". 分析： 思路很简单，就是按位依次相加，处理进位即可，循环条件里 阅读全文
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题目： 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 sequ 阅读全文