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ProjectEulerTS/Problems/Problem15.ts

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//ProjectEulerTS/Problems/Problem15.ts
//Matthew Ellison
// Created: 03-29-21
//Modified: 07-14-21
//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/typescriptClasses
/*
Copyright (C) 2021 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/>.
*/
import { Problem } from "./Problem";
export class Problem15 extends Problem{
//Variables
//Static variables
private static WIDTH: number = 20; //The width of the box to traverse
private static LENGTH: number = 20; //The height of the box to traverse
//Instance variables
private numOfRoutes: number; //The number of routes from 0, 0 to 20, 20
//Functions
//Constructor
public constructor(){
super(`How many routes from the top left corner to the bottom right corner are there through a ${Problem15.WIDTH}x${Problem15.LENGTH} grid if you can only move right and down?`);
this.numOfRoutes = 0;
}
//Operational functions
//Solve the problem
public solve(): void{
//If the problem has already been solved do nothing and end the function
if(this.solved){
return;
}
//Start the timer
this.timer.start();
//We write this as a recursive function
//When in a location it always move right first, then down
this.move(0, 0);
//Stop the timer
this.timer.stop();
//Throw a flag to show the problem is solved
this.solved = true;
}
//This function acts as a handler for moving the position on the grid and counting the disctance
//It moves right first, then down
private move(currentX: number, currentY: number): void{
//Check if you are at the end and act accordingly
if((currentX == Problem15.WIDTH) && (currentY == Problem15.LENGTH)){
++this.numOfRoutes;
return;
}
//Move right if possible
if(currentX < Problem15.WIDTH){
this.move(currentX + 1, currentY);
}
//Move down if possible
if(currentY < Problem15.LENGTH){
this.move(currentX, currentY + 1);
}
}
//Reset the problem so it can be run again
public reset(): void{
super.reset();
this.numOfRoutes = 0;
}
//Gets
//Returns the result of solving the problem
public getResult(): string{
this.solvedCheck("result");
return `The number of routes is ${this.numOfRoutes}`;
}
//Returns the number of routes found
public getNumberOfRoutes(): number{
this.solvedCheck("number of routes");
return this.numOfRoutes;
}
}
/* Results:
The number of routes is 137846528820
It took 37.058 minutes to solve this problem.
*/