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Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which means it moves back to the or 阅读全文
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A self-dividing number is a number that is divisible by every digit it contains. For example, 128 is a self-dividing number because 128 % 1 == 0, 128 阅读全文
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Given a non-negative integer c, your task is to decide whether there're two integers a and b such that a2 + b2 = c. Example 1: Input: 5 Output: True E 阅读全文
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We define the Perfect Number is a positive integer that is equal to the sum of all its positive divisors except itself. Now, given an integer n, write 阅读全文
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Given a non-empty integer array of size n, find the minimum number of moves required to make all array elements equal, where a move is incrementing n 阅读全文
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You have a total of n coins that you want to form in a staircase shape, where every k-th row must have exactly k coins. Given n, find the total number 阅读全文
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Given two non-negative integers num1 and num2 represented as string, return the sum of num1 and num2. Note: The length of both num1 and num2 is < 5100 阅读全文
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Find the nth digit of the infinite integer sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... Note:n is positive and will fit within the range of a 32-bi 阅读全文
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Given a positive integer num, write a function which returns True if num is a perfect square else False. Note: Do not use any built-in library functio 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? 题目标签：Math 题目要 阅读全文