#ProjectEuler/Python/Problem20.py
#Matthew Ellison
# Created: 03-14-19
#Modified: 03-28-19
#What is the sum of the digits of 100!
#Unless otherwise listed, all of my non-standard imports can be gotten from my pyClasses repository at https://bitbucket.org/Mattrixwv/pyClasses
"""
	Copyright (C) 2019  Matthew Ellison

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
"""


from Stopwatch import Stopwatch

__TOP_NUM = 100	#The number that you are trying to find the factorial of


def Problem20():
	num = 1	#Holds the number being calculated
	sumOfNum = 0	#Holds the sum of the digits of num

	#Run through every number from 1 to 100 and multiply it by the current num to get 100!
	for cnt in range(1, __TOP_NUM + 1):
		num *= cnt

	#Get a string of the number because it is easier to pull appart the individual charaters for the sum
	numString = str(num)
	#Run through every character in the string, convert it back to an integer and add it to the running sum
	for char in numString:
		sumOfNum += int(char)

	#Print the results
	print("100! = " + numString)
	print("The sum of the digits is: " + str(sumOfNum))


#This starts the correct function if called directly
if __name__ == "__main__":
	timer = Stopwatch()
	timer.start()
	Problem20()
	timer.stop()
	print("It took " + timer.getString() + " to run this algorithm")

""" Results:
100! = 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000
The sum of the digits is: 648
It took 99.670 microseconds to run this algorithm
"""