class Solution:
def findPairs(self, nums: List[int], k: int) -> int:
ans = 0
if k == 0:
count = {}
for num in nums:
if num not in count:
count[num] = 0
count[num] += 1
for k in count:
if count[k] > 1:
ans += 1
return ans
elif k < 0:
return 0
nums = set(nums)
for num in nums:
if num + k in nums:
ans += 1
if num - k in nums:
ans += 1
return ans // 2