Leetcode 597. Friend Requests I: Overall Acceptance Rate

Given a set of users (typically with an attribute like age) and a deterministic rule that decides whether a friend request from user A to user B is accepted, compute the overall acceptance rate (accepted requests divided by total requests). The challenge is to apply the acceptance rule across all user pairs efficiently (using counting, sorting, or two‑pointer techniques) instead of brute‑forcing O(n^2) checks.