K-diff Pairs in an Array (Leetcode 532)

Problem Link: https://leetcode.com/problems/k-diff-pairs-in-an-array/

class Solution:
    def findPairs(self, nums: List[int], k: int) -> int:
        
        d={}
        for i in nums:
            if(i not in d):
                d[i]=1
            else:
                d[i]+=1
        
        ans=0
        # Here, we are traversing the dictionary, bcoz
        # we need unique pairs
        for i in d:
            
            # If k==0, a unique pair exists if the ele
            # occurs more than 1 time.
            if(k==0 and d[i]>1):
                ans+=1
                
            elif(k>0 and k+i in d):
                ans+=1
        
        return ans