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1. Java2. Pythonclass Solution(object): def reverse(self, x): """ :type x: int :rtype: int """ flag=1 if x<0: x=x*(-1)

Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number,

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.思路：a^b异或等于无进位的加法，(a&b)解法一：public class Solution {

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 integer, replace the number by the sum of the squares

Given a column title as appear in an Excel sheet, return its corresponding column number.For example: A -> 1 B -> 2 C -> 3 ... Z -> 26 AA -> 27 AB -> 28 public c

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

Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element

Given two integers representing the numerator and denominator of a fraction, return the fraction in string format.If the fractional part is repeating, enclose the repeating part in parentheses.

Rotate an array of n elements to the right by k steps.For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].Try to come up as many solutions as you can,

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 list of non negative integers, arrange them such that they form the largest number.For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.Note: The result may be ve

题目Given an array and a value, remove all instances of that value in place and return the new length.Do not allocate extra space for another array, you must do this in place with constant memor

题目：Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.Do not allocate extra space for another array, you must do this in pla

Javapublic class Solution { public int romanToInt(String s) { int res=0; if(s.length()==0) return 0; int[] radix = {1000, 500, 100, 50, 10, 5, 1}; char[] symbol

Javapublic class Solution { public String intToRoman(int num) { int[] radix = {1000, 900, 500, 400, 100, 90,50, 40, 10, 9, 5, 4, 1}; String[] symbol = {"M", "CM", "D", "CD", "C",

1. Javapublic class Solution { public boolean isPalindrome(int x) { if(x<0) return false; return x==reverse(x); } public int reverse(int x) { long sum=0;

Given an array of n positive integers and a positive integer s, find the minimal length of a subarray of which the sum ≥ s. If there isn't one, return 0 instead.For example, given the array [2,3