Concepts of Computer Science

   https://leetcode.com/problems/two-sum/ Given an array of integers  nums  and an integer  target , return  indices of the two numbers such that they add up to  target . You may assume that each input would have  exactly  one solution , and you may not use the  same  element twice. You can return the answer in any order.   Example 1: Input: nums = [2,7,11,15], target = 9 Output: [0,1] Output: Because nums[0] + nums[1] == 9, we return [0, 1]. Example 2: Input: nums = [3,2,4], target = 6 Output: [1,2] Example 3: Input: nums = [3,3], target = 6 Output: [0,1] class Solution {     public int[] twoSum(int[] nums, int target) {              HashMap<Integer,Integer> map=new HashMap<Integer,Integer>();                  for(int i=0;i<nums.length;i++){                      ...

Basics of java in layman term for beginner What is an object ? object is a real world entity. Object is an instance of the class.It means something that is alive. Let us take an example of CAR:- concept of a car is class. I mean we all know that it is having four tyres , one engine , four doors , a seat e.t.c. but we can't do anything just by the concept we need real Car to perform operations on it . This real car is what we call is an object. Explain about main() method in java ? main() method is an entry point of a program. public static void main(String[] args) Why main() method is public, static and void in java ? public: It can be accessed from anywhere. static: no class object need to call this method. void: it is not returning anything in back. What is JIT compiler ? JIT is just in time compiler.JIT compiler runs after the program has started and compiles the code (usually bytecode or some kind of VM instructions) on the fly (or just-...