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Given a non-negative integer n, count all numbers with unique digits, x, where 0 ≤ x < 10n. Example:Given n = 2, return 91. (The answer should be the 阅读全文
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Given two 1d vectors, implement an iterator to return their elements alternately. For example, given two 1d vectors: By calling next repeatedly until 阅读全文
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Given an integer n, return the number of trailing zeroes in n!. Note: Your solution should be in logarithmic time complexity. [分析]首先别忘了什么是factorial，就是 阅读全文
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这题真特么是太难了 解题思路 首先我们先把原数组全部异或起来，那么我们会得到一个数字，这个数字是两个不相同的数字异或的结果，我们取出其中任意一位为‘1’的位，为了方便起见，我们用 a &= -a 来取出最右端为‘1’的位。。。这道题的巧妙之处在于利用x1 ^ x2的结果对原数组进行了分组，进而将x1 阅读全文
摘要：
Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -. Example:Given a = 1 and b = 2, return 3. Credits:Speci 阅读全文