# Challenge name: Single Number
#
# Given a non-empty array of integers nums, every element appears twice
# except for one. Find that single one.
#
# Follow up: Could you implement a solution with a linear runtime
# complexity and without using extra memory?
#
# @param {Integer[]} nums
# @return {Integer}

def single_number(nums)
end
nums = [2, 2, 1]
puts(single_number(nums))
# Output: 1
nums = [4, 1, 2, 1, 2]
puts(single_number(nums))
# Output: 4
nums = [1]
puts(single_number(nums))
# Output: 1