K-diff Pairs in an Array

arrayhash tabletwo pointers

Problem Statement

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]

Notice that |val| denotes the absolute value of val .

Examples

Example 1

Input: nums = [3,1,4,1,5], k = 2
Output: 2
There are two 2-diff pairs in the array, (1, 3) and (3, 5).
Although we have two 1s in the input, we should only return the number of unique pairs.

Example 2

Input: nums = [1,2,3,4,5], k = 1
Output: 4
There are four 1-diff pairs in the array, (1, 2), (2, 3), (3, 4) and (4, 5).

Example 3

Input: nums = [1,3,1,5,4], k = 0
Output: 1
There is one 0-diff pair in the array, (1, 1).

Constraints

1 <= nums.length <= 10 ^4

-10 ^7 <= nums[i] <= 10 ^7

0 <= k <= 10 ^7

🤔

Medium

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicHash Table