--this file is solely a personal work and the codes are highly optimised-- --the ref of these codes is the youtube channel of kunal kushwaha-- --the implementation is done by me only and the code will have little to no errors-- --also this code contains some of many problemsi solved while i was doing DSA in java-- --this file also has solutions that i personally thought of without using leetcode solutions so the code might have some complexity issues but they will run fine-- --also some codes are incomplete i will complete themin future--