961. N-Repeated Element in Size 2N Array

Problem Link

Description

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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

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Python3

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