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106 lines
3.0 KiB
C++
106 lines
3.0 KiB
C++
//ProjectEuler/ProjectEulerCPP/Source/Problem15.hpp
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//Matthew Ellison
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// Created: 09-29-18
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//Modified: 08-28-20
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//How many routes from the top left corner to the bottom right corner are there through a 20×20 grid if you can only move right and down?
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//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/myClasses
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/*
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Copyright (C) 2020 Matthew Ellison
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <cinttypes>
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#include <string>
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#include <sstream>
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#include "Problems/Problem15.hpp"
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int Problem15::WIDTH = 20; //The width of the grid
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int Problem15::LENGTH = 20; //The length of the grid
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//This function acts as a handler for moving the position on the grid and counting the distance
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//It moves right first, then down
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void Problem15::move(int currentX, int currentY){
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//Check if you are at the end
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if((currentX == WIDTH) && (currentY == LENGTH)){
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++numOfRoutes;
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return;
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}
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//Move right if possible
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if(currentX < WIDTH){
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move(currentX + 1, currentY);
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}
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//Move down if possible
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if(currentY < LENGTH){
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move(currentX, currentY + 1);
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}
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}
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//Constructor
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Problem15::Problem15() : Problem("How many routes from the top left corner to the bottom right corner are there through a 20×20 grid if you can only move right and down?"), numOfRoutes(0){
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}
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//Solve the problem
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void Problem15::solve(){
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//If the problem has already been solved do nothing and end the function
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if(solved){
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return;
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}
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//Setup the variables
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int currentX = 0; //The current x location on the grid
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int currentY = 0; //The current y location on the grid
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//Start the timer
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timer.start();
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//We write this as a recursive function
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//When in a location it always moves right first, then down
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move(currentX, currentY);
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//Stop the timer
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timer.stop();
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//Throw a flag to show the problem is solved
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solved = true;
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}
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//Reset the problem so it can be run again
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void Problem15::reset(){
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Problem::reset();
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numOfRoutes = 0;
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}
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//Gets
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//Return a string with the solution to the problem
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std::string Problem15::getResult(){
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if(!solved){
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throw Unsolved();
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}
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std::stringstream result;
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result << "The number of routes is " << numOfRoutes;
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return result.str();
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}
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//Returns the number of routes found
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uint64_t Problem15::getNumberOfRoutes() const{
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//If the problem hasn't been solved throw an exception
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if(!solved){
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throw Unsolved();
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}
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return numOfRoutes;
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}
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