Distinguishing extra element from two arrays?

Question

One of my friend was asked this question in an interview -

• You have given two integer arrays each of size 10.
• Both contains 9 equal elements (say 1 t

Answer 1

Here's some simple pseudocode for a solution. I'm assuming it's OK to modify the arrays and that arrays have a remove(value) method (or that you could write one trivially). It takes the 2 arrays and returns an array containg 2 values, the first is the unique value from the first array and the second is the unique value from the 2nd array.

function findUnique(a:Array, b:Array):Array {
  var uniqueFromA:int;
  var uniqueFromB:int;

  for each(value:int in a) {
    var len:int = b.length;
    b.remove(value);
    /* b's length didn't change, so nothing was removed, so the value doesn't
     * exist in it. */
    if(b.length == len) {
      uniqueFromA = value;
    }
  }

  /* Only the unique value in b still exists in b */
  uniqueFromB = b[0];

  return [uniqueFromA, uniqueFromB];
}