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Leetcode
Easy
Arrays
Bit Manipulation
Single Number
Find the one element that appears exactly once when every other element appears twice.
Acceptance 0%
Problem Statement
Problem
Given an integer array nums, every element appears exactly twice except for one element which appears only once.
Return the element that appears once.
You should aim for a solution with linear time complexity and constant extra space.
Input Format
- An integer array
nums - Each value appears twice except for one distinct value
Output Format
- Return the single element that appears only once
Constraints
1 <= nums.length- Exactly one value appears once
- Every other value appears exactly twice
- Use integer values that fit in standard 32-bit signed integer ranges
Hints
- Think about an operation that cancels out equal values.
- Try to avoid using extra memory proportional to the array size.
Input Format
- An integer array
nums - Exactly one number appears once; all others appear twice
Output Format
- Return the unique number that appears once
Constraints
- Exactly one value appears once
- All other values appear exactly twice
- Target linear time and constant extra space
Examples
Sample cases returned by the problem API.
Example 1
Input
nums = [2,2,1]
Output
1
Explanation
All numbers appear twice except 1, so the answer is 1.
Example 2
Input
nums = [4,1,2,1,2]
Output
4
Explanation
1 and 2 each appear twice, leaving 4 as the unique value.
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