mirror of
https://bitbucket.org/Mattrixwv/projecteulerjava.git
synced 2025-12-06 17:13:58 -05:00
108 lines
3.2 KiB
Java
108 lines
3.2 KiB
Java
//ProjectEulerJava/src/main/java/mattrixwv/ProjectEuler/Problems/Problem15.java
|
||
//Matthew Ellison
|
||
// Created: 03-04-19
|
||
//Modified: 06-27-23
|
||
//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?
|
||
//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/JavaClasses
|
||
/*
|
||
Copyright (C) 2023 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/>.
|
||
*/
|
||
package com.mattrixwv.project_euler.problems;
|
||
|
||
|
||
public class Problem15 extends Problem{
|
||
//Variables
|
||
//Static vaiables
|
||
protected static int gridWidth = 20; //The width of the box to traverse
|
||
protected static int gridLength = 20; //The height of the box to traverse
|
||
//Instance variables
|
||
protected long numOfRoutes; //The number of routes from 0, 0 to 20, 20
|
||
|
||
//Functions
|
||
//Constructor
|
||
public Problem15(){
|
||
super(String.format("How many routes from the top left corner to the bottom right corner are there through a %dx%d grid if you can only move right and down?", gridWidth, gridLength));
|
||
numOfRoutes = 0;
|
||
}
|
||
//Operational functions
|
||
//Solve the problems
|
||
@Override
|
||
public void solve(){
|
||
//If the problem has already been solved do nothing and end the function
|
||
if(solved){
|
||
return;
|
||
}
|
||
|
||
//Start the timer
|
||
timer.start();
|
||
|
||
|
||
//We write this as a recursive function
|
||
//When in a location it always moves right first, then down
|
||
move(0, 0);
|
||
|
||
|
||
//Stop the timer
|
||
timer.stop();
|
||
|
||
//Throw a flag to show the problem is solved
|
||
solved = true;
|
||
}
|
||
//This function acts as a handler for moving the position on the grid and counting the distance
|
||
//It moves right first, then down
|
||
private void move(int currentX, int currentY){
|
||
//Check if you are at the end and act accordingly
|
||
if((currentX == gridWidth) && (currentY == gridLength)){
|
||
++numOfRoutes;
|
||
return;
|
||
}
|
||
|
||
//Move right if possible
|
||
if(currentX < gridWidth){
|
||
move(currentX + 1, currentY);
|
||
}
|
||
|
||
//Move down if possible
|
||
if(currentY < gridLength){
|
||
move(currentX, currentY + 1);
|
||
}
|
||
}
|
||
//Reset the problem so it can be run again
|
||
@Override
|
||
public void reset(){
|
||
super.reset();
|
||
numOfRoutes = 0;
|
||
}
|
||
//Gets
|
||
//Returns the result of solving the problem
|
||
@Override
|
||
public String getResult(){
|
||
solvedCheck("result");
|
||
return String.format("The number of routes is %d", numOfRoutes);
|
||
}
|
||
//Returns the number of routes found
|
||
public long getNumberOfRoutes(){
|
||
solvedCheck("number of routes");
|
||
return numOfRoutes;
|
||
}
|
||
}
|
||
|
||
|
||
/* Results:
|
||
The number of routes is 137846528820
|
||
It took an average of 20.702 minutes to run this problem through 10 iterations
|
||
*/
|