Two elements in array whose xor is maximum

Question

Given an array of integers ,You have to find two elements whose XOR is maximum.

There is naive approach --just by picking each element and xoring with other elemen

Answer 1

Make a recursive function that takes two lists of integers, A and B, as its arguments. As its return value, it returns two integers, one from A and one from B, which maximize the XOR of the two. If all the integers are 0, return (0,0). Otherwise, the function does some processing and calls itself recursively twice, but with smaller integers. In one of the recursive calls, it considers taking an integer from list A to supply a 1 to bit k, and in the other call it considers taking an integer from list B to supply a 1 to bit k.

I don't have time now to fill in the details, but maybe this will be enough for to see the answer? Also, I'm not sure if the run time will be better than N^2, but it probably will be.