Find Single Number
Easy
Given a non-empty array of integers where every element appears twice except for one, find that single one. Write a function that outputs the single element.
Example 1
Input
[ 2, 2, 1 ]
Output
1
Explanation. All elements except 1 appear twice.
Example 2
Input
[ 4, 1, 2, 1, 2 ]
Output
4
Explanation. All elements except 4 appear twice.
Example 3
Input
[ 1 ]
Output
1
Explanation. Only one element in the array, that is the single number.
Example 4
Input
[ -1, -1, -2 ]
Output
-2
Explanation. All elements except -2 appear twice.
Follow-up: Can you implement the solution with a linear runtime complexity and without using extra memory?
Constraints:
The array will always be non-empty and will always have exactly one element that appears only once. Elements can be any integer value, negative or positive.
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