Problem 3 "Planet Mining" Solution

generateData.py

from random import uniform

numberOfCases = 1000
print(numberOfCases + 1)

# an edge case to test for
print('0.1 0.1 1 1')

for i in range(numberOfCases):
	starting_concentration = uniform(0.25, 0.5)
	ending_concentration = uniform(0.001, 0.01)
	volume = uniform(1, 10)
	outflow_rate = uniform(1, 10)
	print('{0:0.3f} {1:0.3f} {2:0.3f} {3:0.3f}'.format(starting_concentration, ending_concentration, volume, outflow_rate))

planet.py

from math import log

N = int(input().strip())
for i in range(N):
	starting_concentration, ending_concentration, volume, outflow_rate = map(float, input().strip().split())

	# the formula for model concentration is exponential, and can be written like this:
	# concentration(t) = concentration(0) * exp(-outflow_rate * t / volume)
	# If we know concentration(t) = ending_concentration, we can solve for t. This is the formula you get
	ending_time = volume / outflow_rate * log(starting_concentration / ending_concentration)

	# now pretty print
	print('{0:0.3f}h'.format(ending_time))