961. N-Repeated Element in Size 2N Array

Easy

You are given an integer array nums with the following properties:

• nums.length == 2 * n.
• nums contains n + 1 unique elements.
• Exactly one element of nums is repeated n times.

Return the element that is repeated n times.

Solution

class Solution:
    def repeatedNTimes(self, nums: List[int]) -> int:
        seen = set()
        for num in nums:
            if num in seen:
                return num
            seen.add(num)