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2006. Count Number of Pairs With Absolute Difference K

Difficulty Topics

Description

Given an integer array nums and an integer k, return the number of pairs (i, j) where i < j such that |nums[i] - nums[j]| == k.

The value of |x| is defined as:

  • x if x >= 0.
  • -x if x < 0.

 

Example 1:

Input: nums = [1,2,2,1], k = 1
Output: 4
Explanation: The pairs with an absolute difference of 1 are:
- [1,2,2,1]
- [1,2,2,1]
- [1,2,2,1]
- [1,2,2,1]

Example 2:

Input: nums = [1,3], k = 3
Output: 0
Explanation: There are no pairs with an absolute difference of 3.

Example 3:

Input: nums = [3,2,1,5,4], k = 2
Output: 3
Explanation: The pairs with an absolute difference of 2 are:
- [3,2,1,5,4]
- [3,2,1,5,4]
- [3,2,1,5,4]

 

Constraints:

  • 1 <= nums.length <= 200
  • 1 <= nums[i] <= 100
  • 1 <= k <= 99

Solution

count-number-of-pairs-with-absolute-difference-k.py
class Solution:
    def countKDifference(self, nums: List[int], k: int) -> int:
        n = len(nums)
        res = 0

        for i in range(n):
            for j in range(i + 1, n):
                if abs(nums[i] - nums[j]) == k:
                    res += 1

        return res