961. N-Repeated Element in Size 2N Array

Description

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.

Example 1:

Input: nums = [1,2,3,3]
Output: 3

Example 2:

Input: nums = [2,1,2,5,3,2]
Output: 2

Example 3:

Input: nums = [5,1,5,2,5,3,5,4]
Output: 5

Constraints:

2 <= n <= 5000
nums.length == 2 * n
0 <= nums[i] <= 10⁴
nums contains n + 1 unique elements and one of them is repeated exactly n times.

Solution

n-repeated-element-in-size-2n-array.py

class Solution:
    def repeatedNTimes(self, nums: List[int]) -> int:
        m = len(nums)
        n = m // 2

        count = Counter(nums)

        for k, v in count.items():
            if v == n:
                return k