Watch 10 video solutions for Count the Number of Fair Pairs, a medium level problem involving Array, Two Pointers, Binary Search. This walkthrough by NeetCodeIO has 15,313 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
Given a 0-indexed integer array nums of size n and two integers lower and upper, return the number of fair pairs.
A pair (i, j) is fair if:
0 <= i < j < n, andlower <= nums[i] + nums[j] <= upper
Example 1:
Input: nums = [0,1,7,4,4,5], lower = 3, upper = 6 Output: 6 Explanation: There are 6 fair pairs: (0,3), (0,4), (0,5), (1,3), (1,4), and (1,5).
Example 2:
Input: nums = [1,7,9,2,5], lower = 11, upper = 11 Output: 1 Explanation: There is a single fair pair: (2,3).
Constraints:
1 <= nums.length <= 105nums.length == n-109 <= nums[i] <= 109-109 <= lower <= upper <= 109