01 2018 档案
摘要：Given two non-negative integers num1 and num2 represented as string, return the sum of num1 and num2. Note: 题意：给定以字符串形式表示的两个非负整数num1和num2，返回这两个整数的和。No
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摘要：Given an m * n matrix M initialized with all 0's and several update operations. Operations are represented by a 2D array, and each operation is repres
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摘要：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
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摘要：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
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摘要：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
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摘要：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
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摘要：Write a program to check whether a given number is an ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For exa
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摘要：Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. For example: Given num = 38, the process is like:
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摘要：Given an integer, write a function to determine if it is a power of two. Credits:Special thanks to @jianchao.li.fighter for adding this problem and cr
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摘要：Write an algorithm to determine if a number is "happy". A happy number is a number defined by the following process: Starting with any positive intege
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