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Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two 阅读全文
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Given a non-negative integer num represented as a string, remove k digits from the number so that the new number is the smallest possible. Note: The l 阅读全文
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You are given two integer arrays nums1 and nums2 sorted in ascending order and an integer k. Define a pair (u,v) which consists of one element from th 阅读全文
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Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string. Example 1: Ex 阅读全文
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Numbers can be regarded as product of its factors. For example, Write a function that takes an integer n and return all possible combinations of its f 阅读全文
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Given an integer (signed 32 bits), write a function to check whether it is a power of 4. Example:Given num = 16, return true. Given num = 5, return fa 阅读全文
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Given an integer, write a function to determine if it is a power of three. Follow up:Could you do it without using any loop / recursion? Credits:Speci 阅读全文
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Given an integer, write a function to determine if it is a power of two. Example 1: Example 2: Example 3: 给一个整数，写一个函数来判断它是否为2的次方数。 利用计算机用的是二进制的特点，用位操作 阅读全文
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Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built with those letters. This 阅读全文
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Given a string s, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can f 阅读全文