#2563

Count the Number of Fair Pairs

specialist · 830 · lc medium +31 · verified · 52.7% accepted · 2,010 likes · top 43%

⚑ Converging Pointers (Pair / Triple Sum)

Description

Given a 0-indexed integer array nums and bounds lower and upper, count the number of index pairs (i, j) with i < j such that lower <= 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).

Code

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class Solution:
    def countFairPairs(self, nums: List[int], lower: int, upper: int) -> int:

class Solution:
    def countFairPairs(self, nums: List[int], lower: int, upper: int) -> int: