public class SingleInArray {

public static void main(String[] args) {

int[] arr = { 1, 1, 2, 3, 3, 4, 4, 8, 8 };

System.out.println(findSingle(arr));

}

/**

* 1. Initialize SUM to 0.

* 2. Iterate over the array (for or while loop) with a step size of +2

* (increment of index by 2).

* 2.1. Add the current element (i th element) to SUM. And subtract the next

* element ( the element at (i+1) index) from SUM.

* 3. Return SUM as being the lonely value.

*

* @param a

* @return unique element of array

*/

static int findSingle(int[] a) {

int sum = 0;

try {

for (int i = 0; i < a.length; i += 2) {

sum += a[i];

sum -= a[i + 1];

}

} catch (ArrayIndexOutOfBoundsException e) {

System.out.println("Well expected to run beyond index");

}

return sum;

}

}