Added solution to problem 15

src/Problems/Problem15.rs

@@ -0,0 +1,79 @@
+//ProjectEulerRust/src/Problems/Problems15.rs
+//Matthew Ellison
+// Created: 06-16-20
+//Modified: 06-16-20
+//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/RustClasses
+/*
+	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/>.
+*/
+
+
+extern crate myClasses;
+use crate::Problems::Answer::Answer;
+
+
+static WIDTH: i32 = 20;
+static LENGTH: i32 = 20;
+
+pub fn getDescription() -> String{
+	"Which starting number, under one million, produces the longest chain using the itterative sequence?".to_string()
+}
+
+pub fn solve() -> Answer{
+	//Setup the rest of the variables
+	let currentX = 0;	//The current x location on the grid
+	let currentY = 0;	//The current y location on the grid
+	let mut numOfRoutes = 0i64;
+
+	//Start the timer
+	let mut timer = myClasses::Stopwatch::Stopwatch::new();
+	timer.start();
+
+	//We write this as a recursive function
+	//When in a location it always move right first, then down
+	moveLoc(currentX, currentY, &mut numOfRoutes);
+
+	//Stop the timer
+	timer.stop();
+
+	//Return the results
+	return Answer::new(format!("The number of routes is {}", numOfRoutes), timer.getString());
+}
+
+//This function acts as a handler for moving the position on the grid and counting the distance
+//It moves right first, then down
+fn moveLoc(currentX: i32, currentY: i32, numOfRoutes: &mut i64){
+	//Check if you are at the end and act accordingly
+	if((currentX == WIDTH) && (currentY == LENGTH)){
+		*numOfRoutes += 1;
+		return;
+	}
+
+	//Move right if possible
+	if(currentX < WIDTH){
+		moveLoc(currentX + 1, currentY, numOfRoutes);
+	}
+	//Move down if possible{
+	if(currentY < LENGTH){
+		moveLoc(currentX, currentY + 1, numOfRoutes);
+	}
+}
+
+/* Results:
+The number of routes is 137846528820
+It took 11.804 minutes to solve this problem
+*/