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LeetCode 532, Medium. Topics: Array, Hash Table, Two Pointers, Binary Search, Sorting. View on LeetCode. Generate this problem as a practice environment: tested reference solution, 16 parametrized pytest cases, and a playground notebook:

Problem

Given an array of integers nums and an integer k, return the number of unique k-diff pairs in the array. A k-diff pair is an integer pair (nums[i], nums[j]), where the following are true:
  • 0 <= i, j < nums.length
  • i != j
  • |nums[i] - nums[j]| == k
Notice that |val| denotes the absolute value of val.

Examples

Constraints

  • 1 <= nums.length <= 10^4
  • -10^7 <= nums[i] <= 10^7
  • 0 <= k <= 10^7

Solution

Reference implementation from solution.py on GitHub, full suite in test_solution.py:

Complexity

Tags

Last modified on September 7, 2026