leetcode 解题思路

Given an integer, write an algorithm to convert it to hexadecimal. For negative integer,two’s complementmethod is used.Note:All letters in hexadecimal (a-f) must be in lowercase. The hexadecimal string must not contain extra leading0s. If the numbe...

Calculate the sum of two integersaandb, but you arenot allowedto use the operator+and-.思路：用XOR来进行加计算，类似： 1+2 = 0001 + 0010 = 0011 = 3，进位，用&然后，tricky的地方在于 while循环是用b来判断是否为0，而且carry用

Given a non negative integer numbernum. For every numbersiin the range0 ≤ i ≤ numcalculate the number of 1's in their binary representation and return them as an array.Example 1:Input: 2Output: [0,1,1]Example 2:Input: 5Output: [0,1,1,2,1,2...

Given two stringssandtwhich consist of only lowercase letters.Stringtis generated by random shuffling stringsand then add one more letter at a random position.Find the letter that was

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 using

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 extra ...

Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as theHamming weight).For example, the 32-bit integer ’11' has binary representation000000

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 should run...

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

Divide two integerswithout using multiplication, division and mod operator.If it will overflow(exceeding 32-bit signed integer representation range), return2147483647The integer division should ...

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 nums =

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

Reverse bits of a given 32 bits unsigned integer.For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as0011100101