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2465. Number of Distinct Averages

Difficulty Topics

Description

You are given a 0-indexed integer array nums of even length.

As long as nums is not empty, you must repetitively:

  • Find the minimum number in nums and remove it.
  • Find the maximum number in nums and remove it.
  • Calculate the average of the two removed numbers.

The average of two numbers a and b is (a + b) / 2.

  • For example, the average of 2 and 3 is (2 + 3) / 2 = 2.5.

Return the number of distinct averages calculated using the above process.

Note that when there is a tie for a minimum or maximum number, any can be removed.

 

Example 1:

Input: nums = [4,1,4,0,3,5]
Output: 2
Explanation:
1. Remove 0 and 5, and the average is (0 + 5) / 2 = 2.5. Now, nums = [4,1,4,3].
2. Remove 1 and 4. The average is (1 + 4) / 2 = 2.5, and nums = [4,3].
3. Remove 3 and 4, and the average is (3 + 4) / 2 = 3.5.
Since there are 2 distinct numbers among 2.5, 2.5, and 3.5, we return 2.

Example 2:

Input: nums = [1,100]
Output: 1
Explanation:
There is only one average to be calculated after removing 1 and 100, so we return 1.

 

Constraints:

  • 2 <= nums.length <= 100
  • nums.length is even.
  • 0 <= nums[i] <= 100

Solution

number-of-distinct-averages.py
class Solution:
    def distinctAverages(self, nums: List[int]) -> int:
        N = len(nums)
        nums.sort()
        s = set()

        for i in range(N // 2):
            s.add((nums[i] + nums[~i]) / 2)

        return len(s)