#ProjectEuler/Python/Problem20.py
#Matthew Ellison
# Created: 03-14-19
#Modified: 07-19-20
#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) 2020  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 Problems.Problem import Problem
from Stopwatch import Stopwatch
from Unsolved import Unsolved


class Problem20(Problem):
	#Variables
	__top_num = 100	#The number that you are trying to find the factorial of

	#Functions
	#Constructor
	def __init__(self):
		super().__init__("What is the sum of the digits of 100!?")
		self.num = 1	#Holds the number 100!
		self.sum = 0	#The sum of the digts of num

	#Operational functions
	#Solve the problem
	def solve(self):
		#If the problem has already been solved do nothing and end the function
		if(self.solved):
			return

		#Start the timer
		self.timer.start()

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

		#Get a string of the number because it is easier to pull appart the individual charaters for the sum
		numString = str(self.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:
			self.sum += int(char)

		#Stop the timer
		self.timer.stop()

		#Save the results
		self.result = "100! = " + numString + "\nThe sum of the digits is: " + str(self.sum)

		#Throw a flag to show the problem is solved
		self.solved = True
	#Reset the problem so it can be run again
	def reset(self):
		super().reset()
		self.num = 1
		self.sum = 0

	#Gets
	#Returns the number 100!
	def getNumber(self) -> int:
		#If the problem hasn't been solved throw an exception
		if(not self.solved):
			raise Unsolved("You must solve the problem before you can get the number")
		return self.num
	#Returns the sum of the digits of 100!
	def getSum(self) -> int:
		#If the problem hasn't been solved throw an exception
		if(not self.solved):
			raise Unsolved("You must solve the problem before you can get the sum")
		return self.sum

#This starts the correct function if called directly
if __name__ == "__main__":
	problem = Problem20()
	print(problem.getDescription())	#Print the description of the problem
	problem.solve()	#Solve the problem
	#Print the results
	print(problem.getResult())
	print("It took " + problem.getTime() + " to solve this algorithm")

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