def on_segment(point_1, point_2, point_3)
  min_x(point_1, point_2) <= point_3[0] &&
  point_3[0] <= max_x(point_1, point_2) &&
  min_y(point_1, point_2) <= point_3[1] &&
  point_3[1] <= max_y(point_1, point_2)
end

def min_x(point_1, point_2)
  [point_1[0], point_2[0]].min
end

def max_x(point_1, point_2)
  [point_1[0], point_2[0]].max
end


# Łukasz
def on_segment(point_1, point_2, point_3)
  point_3[0].between?(x_cords) &&
  point_3[1].between?(y_cords)
end

def x_cords
  (min_x(point_1, point_2), max_x(point_1, point_2))
end

def y_range
  (min_y(point_1, point_2), max_y(point_1, point_2))
end