Using one loop, write a function int uniqueNumber(int[] array). The input of this function is an int array. This array contains only positive integers. Given that every element in this array appeared twice, except for one unique element which appeared only once. Your job is to find and return this unique number.

If every number in this array appeared twice, return -1.

If you can solve this problem using only 1 loop, youll get 5 extra points.

Sample input/output:

Input [3, 3, 2, 4, 4]

Output 2

public class UniqueNumber { public int uniqueNumber (int[]array) { /* Your code goes here*/ } }