Single NumberEasy

Single Number

Easy 13.8k71% acceptance

ArrayBit Manipulation

Given a non-empty array nums in which every element appears exactly twice except for one element that appears once, return that single element.

Aim for linear time and constant extra space.

Example 1

Input: nums = [2,2,1]

Output: 1

Example 2

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

Output: 4

1 and 2 each appear twice; 4 is the loner.

Example 3

Input: nums = [7]

Output: 7

Constraints

1 ≤ nums.length ≤ 3·10⁴
-3·10⁴ ≤ nums[i] ≤ 3·10⁴
Every element appears twice except one.

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Case 1

[2,2,1]

expected: 1

Case 2

[4,1,2,1,2]

expected: 4

Case 3

[7]

expected: 7

Case 4

[-1,-1,-2]

expected: -2

Case 5

[0,1,0]

expected: 1

Case 6

[5,3,5,4,3]

expected: 4