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LeetCode 136 Single Number - Easy

136. Single Number -- Easy

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136. Single Number — Easy

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Problem

  1. Single Number -- Easy

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

Follow up: Could you implement a solution with a linear runtime complexity and without using extra memory?

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.

Solution

### Bit Manipulation with XOR
class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        a = 0
        for i in nums:
            a ^= i
        return a

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