//ProjectEuler/ProjectEulerCPP/Source/Problem31.cpp
//Matthew Ellison
// Created: 06-19-20
//Modified: 07-09-20
//How many different ways can £2 be made using any number of coins?
//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/myClasses
/*
	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/>.
*/


#include <string>
#include <sstream>
#include <vector>
#include "../Headers/Problem31.hpp"


//The value of coins we want
int Problem31::desiredValue = 200;

//Constructor
Problem31::Problem31() : Problem("How many different ways can 2 pounds be made using any number of coins?"){
	permutations = 0;
}

//Solve the problem
void Problem31::solve(){
	//If the problem has alread been solved do nothing and end the function
	if(solved){
		return;
	}

	//Start the timer
	timer.start();

	//Start with 200p and remove the necessary coins with each loop
	for(int pound2 = desiredValue;pound2 >= 0;pound2 -= 200){
		for(int pound1 = pound2;pound1 >= 0;pound1 -= 100){
			for(int pence50 = pound1;pence50 >= 0;pence50 -= 50){
				for(int pence20 = pence50;pence20 >= 0;pence20 -= 20){
					for(int pence10 = pence20;pence10 >= 0;pence10 -= 10){
						for(int pence5 = pence10;pence5 >= 0;pence5 -= 5){
							for (int pence2 = pence5; pence2 >= 0; pence2 -= 2){
								++permutations;
							}
						}
					}
				}
			}
		}
	}


	//Stop the timer
	timer.stop();

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

//Reset the problem so it can be run again
void Problem31::reset(){
	Problem::reset();
	permutations = 0;
}

//Return a string with the solution to the problem
std::string Problem31::getString() const{
	//If the problem hasn't been solved throw an exception
	if(!solved){
		throw unsolved();
	}

	std::stringstream results;
	results << "There are " << permutations << " ways to make 2 pounds with the given denominations of coins";

	return results.str();
}

//Returns the number of correct permutations of the coins
int Problem31::getPermutations() const{
	return permutations;
}