Please design the algorithm in pseudo code

We are given n > 2 wireless sensors modelled as points on a 1D line and every point has a distinct location modelled as a positive x-coordinate. These sensors are given as a sorted array A. Each wireless sensor has the same broadcast radius r. Two wireless sensors can send messages to each other if their locations are at most distance r apart. Your task is to design an algorithm that returns all pairs of sensors that can com- municate with each other, possibly by having their messages forwarded via some of the intermediate sensors. For full marks your algorithm needs to run in O(n?) time. Example: 1 2 3 4 5 6 7 8 9 10 11 12 A : (1,4,5,8,9,10,12], r = 2: return {{1,2}, {3,4}, {3,5},{3,6}, {4,5}, {4,6},{5,6}}. Note that A[3] and A[6] communicate via A [5]. a) Design an algorithm that solves the problem. b) Briefly argue the correctness of your algorithm. c) Analyse the running time of your algorithm