Single Number
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 linear runtime complexity and use only constant extra space.

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Single Number
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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 linear runtime complexity and use only constant extra space.

Example 1:
Input: [2,2,1]
Output: 1
Constraints:

  • 1≤nums.length≤3×1041 \leq \text{nums.length} \leq 3 \times 10^4

  • −3×104≤nums[i]≤3×104-3 \times 10^4 \leq \text{nums}[i] \leq 3 \times 10^4

  • Each element appears twice except for one, which appears once.

  • Solution must use linear runtime and constant extra space.

Input
arr =[2,2,1]

Initialize result = 0. XOR properties: a ^ a = 0, a ^ 0 = a

Input Array
2
2
1
Running XOR Result

0

Binary: 00000000

XOR Properties:

a ^ a = 0 (same numbers cancel out)

a ^ 0 = a (XOR with 0 gives original)

XOR is commutative and associative

Current
Processed
Variables
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DepthFunction Call
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