Solution for Devcon C-Cup Problem A

C_cup_problemA.rb

gets.to_i.times do
    q = gets.to_i
    sum_x, sum_y, sum_x2, sum_xy = 0, 0, 0, 0
    q.times do
        x,y=gets.split.map(&:to_f)
        sum_x += x
        sum_y += y
        sum_x2 += x**2
        sum_xy += x*y
    end
	
    mx = sum_x / q
    my = sum_y / q
    a = (sum_xy - sum_x * my) / (sum_x2 - sum_x * mx)
    b = my - a * mx
    
    a,b = [a,b].map {|p| p.to_i == p ? p.to_i : (p * 100).floor / 100.0}
    puts "#{a} #{b}"
end