Added solution to problem 31

src/Problems.rs

@@ -53,4 +53,5 @@ pub mod Problem27;
 pub mod Problem28;
 pub mod Problem29;
 pub mod Problem30;
+pub mod Problem31;
 pub mod Problem67;

src/Problems/Problem31.rs

@@ -0,0 +1,66 @@
+//ProjectEulerRust/src/Problems/Problems31.rs
+//Matthew Ellison
+// Created: 06-19-20
+//Modified: 06-19-20
+//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/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;
+
+pub fn getDescription() -> String{
+	"Find the sum of all the numbers that can be written as the sum of the fifth powers of their digits.".to_string()
+}
+
+pub fn solve() -> Answer{
+	let desiredValue = 200;
+	let mut permutations = 0;
+
+	//Start the timer
+	let mut timer = myClasses::Stopwatch::Stopwatch::new();
+	timer.start();
+
+	//Start with 200p and remove the necessary coins with each loop
+	for pound2 in (0..=desiredValue).rev().step_by(200){
+		for pound1 in (0..=pound2).rev().step_by(100){
+			for pence50 in (0..=pound1).rev().step_by(50){
+				for pence20 in (0..=pence50).rev().step_by(20){
+					for pence10 in (0..=pence20).rev().step_by(10){
+						for pence5 in (0..=pence10).rev().step_by(5){
+							for _pence2 in (0..=pence5).rev().step_by(2){
+								permutations += 1;
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+
+	//Stop the timer
+	timer.stop();
+
+	return Answer::new(format!("There are {} ways to make 2 pounds with the given denominations of coins", permutations), timer.getString());
+}
+
+/* Results:
+There are 73682 ways to make 2 pounds with the given denominations of coins
+It took 109.300 microseconds to solve this problem
+*/

src/main.rs

@@ -33,10 +33,10 @@ mod Problems;
 #[derive(PartialEq)]
 enum Selections{EMPTY, SOLVE, DESCRIPTION, LIST, EXIT, SIZE}
 
-static problemNumbers: [u32; 32] = [ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,
+static problemNumbers: [u32; 33] = [ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,
 									10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
 									20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
-									30, 67];
+									30, 31, 67];
 
 fn main(){
 	let mut selection = Selections::EMPTY;
@@ -253,6 +253,10 @@ fn solveProblem(problemNumber: u32){
 		println!("{}", Problems::Problem30::getDescription());
 		println!("{}", Problems::Problem30::solve());
 	}
+	else if(problemNumber == 31){
+		println!("{}", Problems::Problem31::getDescription());
+		println!("{}", Problems::Problem31::solve());
+	}
 	else if(problemNumber == 67){
 		println!("{}", Problems::Problem67::getDescription());
 		println!("{}", Problems::Problem67::solve());
@@ -372,6 +376,9 @@ fn printDescription(problemNumber: u32){
 	else if(problemNumber == 30){
 		println!("{}", Problems::Problem30::getDescription());
 	}
+	else if(problemNumber == 31){
+		println!("{}", Problems::Problem31::getDescription());
+	}
 	else if(problemNumber == 67){
 		println!("{}", Problems::Problem67::getDescription());
 	}