how you people are getting 0.001 Though I have used nlog(2*MAX_X) solution I am getting around 0.015 to 0.031 My approach : 1 . Make all coordinates > 0 and xi = MAX_X - x1+1 2 . process the points in increasing y and for same y increasing x 3 . maintain BIT [0..MAX_X] and do query and update in log
