Find the only uncoupled integer in an array.

Problem Statement

Write a program that, given a list of integers as an argument to STDIN

• n1, n2, n3, ..

Prints out the only uncoupled (unpaired) integer in the list to STDOUT.

Example 1:

Given the input

1, 2, 3, 1, 2

your program should output:

3

Example 2:

Given the input

1, 2, 3, 4, 5, 99, 1, 2, 3, 4, 5

your program should output:

99

Hints

• It is possible to solve this with

  Time: O(n) and Space: O(1)

  So before diving into a hashtable solution, take a refresher on Bitwise Operations