Given an positive integer n and k. Find maximum xor of 1 to n using at most k numbers. Xor sum of 1 to n is defined as 1 ^ 2 ^ 3 ^ … ^ n. Examples : Input : n = 4, k = 3 Output : 7 Explanation Maximum possible xor sum is 1 ^ 2 ^ 4 = 7. Input : n = 11, k = 1 Output : 11 Explanation Maximum Possible xor sum is 11. Maximum XOR using K numbers from 1 to n : https://www.geeksforgeeks.org/maximum-xor-using-k-numbers-1-n/