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136. Single Number

Easy

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.

Example 1:

Input: nums = [2,2,1]

Output: 1

Example 2:

Input: nums = [4,1,2,1,2]

Output: 4

Example 3:

Input: nums = [1]

Output: 1

Constraints:

Solution

object Solution {
    def singleNumber(nums: Array[Int]): Int = {
        nums.foldLeft(0)(_ ^ _)
    }
}