# 2006. Count Number of Pairs With Absolute Difference K ###### tags: `Leetcode` `Easy` `HashMap` Link: https://leetcode.com/problems/count-number-of-pairs-with-absolute-difference-k/description/ ## Code ```java= class Solution { public int countKDifference(int[] nums, int k) { int ans = 0; Map<Integer, Integer> cnt = new HashMap<>(); for(int num:nums){ ans += cnt.getOrDefault(num-k, 0)+cnt.getOrDefault(num+k, 0); cnt.put(num, cnt.getOrDefault(num, 0)+1); } return ans; } } ``` ```defaultdict()```括号里要设置默认值, 如果是int就会默认是0 ```python= class Solution: def countKDifference(self, nums: List[int], k: int) -> int: ans = 0 cnt = defaultdict(int) for num in nums: ans += cnt[num-k]+cnt[num+k] cnt[num] += 1 return ans ```