Unique Element Finder

EASY10 pts

You are given a non-empty array of integers called nums, where every element appears exactly twice except for one element that appears only once. Your task is to identify and return the element that appears just once.

The challenge requires you to design a solution that achieves:

Linear time complexity: O(n), where n is the length of the array
Constant space complexity: O(1), meaning you should not use any additional data structures that scale with input size

This constraint eliminates straightforward approaches like using hash maps or sorting, pushing you to think about more elegant bit manipulation techniques.

Example

Input

nums = [2,2,1]

Output

1

Explanation

In this array, the element 2 appears twice at indices 0 and 1, while the element 1 appears only once at index 2. Therefore, 1 is the unique element that we should return.

Example

Input

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

Output

4

Explanation

The element 1 appears at indices 1 and 3, the element 2 appears at indices 2 and 4, but the element 4 appears only once at index 0. Hence, 4 is the unique element.

Example

Input

nums = [1]

Output

1

Explanation

The array contains only a single element, which by definition must be the unique one. Since there are no duplicates, we simply return 1.

Accepted0/0·0% Acceptance

Constraints

1 ≤ nums.length ≤ 3 × 10⁴
-3 × 10⁴ ≤ nums[i] ≤ 3 × 10⁴
Every element appears exactly twice except for one element which appears exactly once.

Code

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Solutions

14px

Test Cases3

Results

Submissions

nums =

[2,2,1]

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Unique Element Finder

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Unique Element Finder

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