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Given an array of integers, every element appears twice except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without using ext

All DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, for example: "ACGAATTCCG". When studying DNA, it is sometimes useful to identify repeated sequences within the DNA.Wri

Given a positive integer n and you can do operations as follow:If n is even, replace n with n/2.If n is odd, you can replace n with either n + 1 or n - 1.What is the minimum number o

A binary watch has 4 LEDs on the top which represent the hours (0-11), and the 6 LEDs on the bottom represent the minutes (0-59).Each LED represents a zero or one, with the least significant bit o

Given an array of numbers nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find the two elements that appear only once.For example:Given 

Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1's in their binary representation and return them as an array.Example:For num = 5

Given a string array words, find the maximum value of length(word[i]) * length(word[j]) where the two words do not share common letters. You may assume that each word will contain only lower case lett

Given a range [m, n] where 0 For example, given the range [5, 7], you should return 4.Credits:Special thanks to @amrsaqr for adding this problem and creating all test cases.如果m, n不同，那么肯定包含

Given a non-empty array of numbers, a0, a1, a2, … , an-1, where 0 ≤ ai < 231.Find the maximum result of ai XOR aj, where 0 ≤ i, j n.Could you do this in O(n) runtime?Example:Input:

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 false.Follow up: Could you solve it without

A character in UTF8 can be from 1 to 4 bytes long, subjected to the following rules:For 1-byte character, the first bit is a 0, followed by its unicode code.For n-bytes character, the first n-bits

Given an integer, write an algorithm to convert it to hexadecimal. For negative integer, two’s complement method is used.Note:All letters in hexadecimal (a-f) must be in lowercase.The hexade

Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.Note:The given integer is guaranteed to fit within the range

Given an array of integers, every element appears three times except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without usi

Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times.You may assume that the array is non-empty and the majority element

Given two strings s and t which consist of only lowercase letters.String t is generated by random shuffling string s and then add one more letter at a random position.Find the letter that was

Given a set of distinct integers, nums, return all possible subsets.Note: The solution set must not contain duplicate subsets.For example,If nums = [1,2,3], a solution is:[ [3], [1],

Write a function to generate the generalized abbreviations of a word.Example:Given word = "word", return the following list (order does not matter):["word", "1ord", "w1rd", "wo1d", "wor1

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:Special thanks to @fujiaozhu for adding this

Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight).For example, the 32-bit integer ’11' has binary representation 000000

The Hamming distance between two integers is the number of positions at which the corresponding bits are different.Given two integers x and y, calculate the Hamming distance.Note:0 ≤ x,

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.For example,Given nums = [0, 1, 3] return 2.Note:Your algorithm shoul

Reverse bits of a given 32 bits unsigned integer.For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as 001110010

The Hamming distance between two integers is the number of positions at which the corresponding bits are different.Now your job is to find the total Hamming distance between all pairs of the giv