BouncingBalls.py

# A child is playing with a ball on the nth floor of a tall building. The height of this floor above ground level, h, is known.

# He drops the ball out of the window. The ball bounces (for example), to two-thirds of its height (a bounce of 0.66).

# His mother looks out of a window 1.5 meters from the ground.

# How many times will the mother see the ball pass in front of her window (including when it's falling and bouncing?

# Three conditions must be met for a valid experiment:
# Float parameter "h" in meters must be greater than 0
# Float parameter "bounce" must be greater than 0 and less than 1
# Float parameter "window" must be less than h.
# If all three conditions above are fulfilled, return a positive integer, otherwise return -1.

# Note:
# The ball can only be seen if the height of the rebounding ball is strictly greater than the window parameter.

# Examples:
# - h = 3, bounce = 0.66, window = 1.5, result is 3

# - h = 3, bounce = 1, window = 1.5, result is -1 

# (Condition 2) not fulfilled).

def bouncing_ball(h, bounce, window):
     if h != 0 and bounce > 0 and bounce < 1 and window < h:
      count = 1
      current = h*bounce
      while current > window:
       current *= bounce
       count += 2
      return count 
     else: return -1