notes/OJ notes/pages/Leetcode Single-Number.md

Leetcode Single-Number

2022-07-22 15:31

Algorithms:

#algorithm #bit_manipulation

Data structures:

#DS #bitset

Difficulty:

#coding_problem #difficulty-easy

Additional tags:

#leetcode

Revisions:

N/A

Related topics:

tag:#bit_manipulation

Links:

• Link to problem
• Learn about XOR

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Problem

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.

Examples

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

• 1 <= nums.length <= 3 * 104
• -3 * 104 <= nums[i] <= 3 * 104
• Each element in the array appears twice except for one element which appears only once.

Thoughts

[!summary] This is a #bit_manipulation problem utilizing the XOR operator

Solution