Count Distinct Value Pairs with a Fixed Gap

### Problem Return the number of distinct unordered value pairs in nums whose absolute difference is k. The two occurrences used by a pair must have different indices; repeated copies of the same value pair are counted only once. ```cpp class Solution { public: int findPairs(vector<int>& nums, int k); }; ``` ### Examples **Example 1:** ```text nums = [0,2,2,4,6], k = 2 Output: 3 Explanation: The distinct pairs are (0,2), (2,4), (4,6). ``` **Example 2:** ```text nums = [5,5,5,7], k = 0 Output: 1 Explanation: Only (5,5) has two distinct occurrences. ``` ### Constraints - Array size: 1..10000. Values: -10000000..10000000. Required gap k: 0..10000000. ### Clarifying Questions Separate the k=0 duplicate-occurrence requirement from positive gaps and count unique value pairs. ```hint Read the boundary condition For a positive gap, which member can uniquely identify an unordered pair? ``` ### Contract considerations Separate the k=0 duplicate-occurrence requirement from positive gaps and count unique value pairs.