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N Repeated Element In Size 2n Array

Find the element that appears exactly n times in an array of length 2n where every other element appears once.

Acceptance 100%
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Problem Statement

Problem

You are given an integer array nums of length 2n.

Exactly one value appears n times, and every other value appears exactly once.

Return the value that is repeated n times.

Notes

  • The repeated value is guaranteed to exist.
  • Any valid solution should identify it efficiently without relying on sorting the entire array unless you choose to.

Input Format

  • A single integer array nums of length 2n.
  • The array contains one value repeated exactly n times.
  • All other values appear once.

Output Format

  • Return the integer value that appears n times in the array.

Constraints

  • 2 <= nums.length <= $10^{4}$
  • nums.length is even
  • 1 <= nums[i] <= $10^{5}$
  • Exactly one value appears n times
  • Every other value appears exactly once
Examples
Sample cases returned by the problem API.

Example 1

Input

nums = [1,2,3,3]

Output

3

Explanation

The array length is 4, so n = 2. The value 3 appears twice, and the others appear once.

Example 2

Input

nums = [5,1,5,2,5,3,5,4]

Output

5

Explanation

The array length is 8, so n = 4. The value 5 appears 4 times, which is exactly n.

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