PHP Compiler Testing
Find the Odd Integer

Create a function that takes a list and finds the integer which appears an odd number of times.

Examples

find_odd([1, 1, 2, -2, 5, 2, 4, 4, -1, -2, 5]) ➞ -1

 

find_odd([20, 1, 1, 2, 2, 3, 3, 5, 5, 4, 20, 4, 5]) ➞ 5

 

find_odd([10]) ➞ 10