//ProjectEuler/C++/Headers/Problem26.cpp
//Matthew Ellison
// Created: 07-28-19
//Modified: 07-28-19
//Find the value of d < 1000 for which 1/d contains the longest recurring cycle in its decimal fraction part.
//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/myClasses
/*
	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/>.
*/


#include <string>
#include <sstream>
#include <vector>
#include "Algorithms.hpp"
#include "../Headers/Problem26.hpp"


unsigned int Problem26::TOP_NUMBER = 999;

Problem26::Problem26() : Problem("Find the value of d < 1000 for which 1/d contains the longest recurring cycle in its decimal fraction part."), longestCycle(0), longestNumber(1){

}

void Problem26::solve(){
	//If the problem has already been solved do nothing and end the function
	if(solved){
		return;
	}

	//Start the timer
	timer.start();

	//Start with 1/2 and find out how long the longest cycle is by checking the remainders
	//Loop through every number from 2-999 and use it for the denominator
	for(unsigned int denominator = 2;denominator <= TOP_NUMBER;++denominator){
		std::vector<unsigned int> remainderList;	//Holds the list of remainders
		bool endFound = false;	//Holds whether we have found an end to the number (either a cycle or a 0 for remainder)
		bool cycleFound = false;	//Holds whether a cycle was detected
		unsigned int numerator = 1;	//The numerator that will be divided
		while(!endFound){
			//Get the remainder after the division
			unsigned int remainder = numerator % denominator;
			//Check if the remainder is 0
			//If it is set the flag
			if(remainder == 0){
				endFound = true;
			}
			//Check if the remainder is in the list
			//If it is in the list, set the appropriate flags
			else if(mee::isFound(remainderList, remainder)){
				endFound = true;
				cycleFound = true;
			}
			//Else add it to the list
			else{
				remainderList.push_back(remainder);
			}
			//Multiply the remainder by 10 to continue finding the next remainder
			numerator = remainder * 10;
		}
		//If a cycle was found check the size of the list against the largest cycle
		if(cycleFound){
			//If it is larger than the largest, set it as the new largest
			if(remainderList.size() > longestCycle){
				longestCycle = remainderList.size();
				longestNumber = denominator;
			}
		}
	}

	//Stop the timer
	timer.stop();

	//Throw a flag to show the problem is solved
	solved = true;
}

std::string Problem26::getString() const{
	//If the problem hasn't been solved throw an exception
	if(!solved){
		throw unsolved();
	}

	std::stringstream results;
	results << "The longest cycle is " << longestCycle << " digits long\n"
			<< "It is started with the number " << longestNumber;

	return results.str();
}

unsigned int Problem26::getLongestCycle() const{
	//If the problem hasn't been solved throw an exception
	if(!solved){
		throw unsolved();
	}
	return longestCycle;
}

unsigned int Problem26::getLongestNumber() const{
	//If the problem hasn't been solved throw an exception
	if(!solved){
		throw unsolved();
	}
	return longestNumber;
}