Added solution for problem 27

src/Problems.rs

@@ -49,3 +49,4 @@ pub mod Problem23;
 pub mod Problem24;
 pub mod Problem25;
 pub mod Problem26;
+pub mod Problem27;

src/Problems/Problem27.rs

@@ -0,0 +1,76 @@
+//ProjectEulerRust/src/Problems/Problems27.rs
+//Matthew Ellison
+// Created: 06-17-20
+//Modified: 06-17-20
+//Find the product of the coefficients, |a| < 1000 and |b| <= 1000, for the quadratic expression that produces the maximum number of primes for consecutive values of n, starting with n=0.
+//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 product of the coefficients, |a| < 1000 and |b| <= 1000, for the quadratic expression that produces the maximum number of primes for consecutive values of n, starting with n=0".to_string()
+}
+
+pub fn solve() -> Answer{
+	let mut topA = 0;	//The A for the most n's generated
+	let mut topB = 0;	//The B for the most n's generated
+	let mut topN = 0;	//The most n's generated
+	let primes = myClasses::Algorithms::getPrimes(12000);	//A list of all primes that could possible be generated with this formula
+
+	//Start the timer
+	let mut timer = myClasses::Stopwatch::Stopwatch::new();
+	timer.start();
+
+	//Start with the lowest possible A and check all possibilities after that
+	for a in -999..=999{
+		//Start with the lowest possible B and check all possibilities after that
+		for b in -1000..=1000{
+			//Start with n=0 and check the formula to see how many primes you can get with concecutive n's
+			let mut n = 0;
+			let mut quadratic = (n * n) + (a * n) + b;
+			while(primes.contains(&quadratic)){
+				n += 1;
+				quadratic = (n * n) + (a * n) + b;
+			}
+			n -= 1;	//Remove an n because the last formula failed
+
+			//Set all the largest number if this created more primes than any other
+			if(n > topN){
+				topN = n;
+				topB = b;
+				topA = a;
+			}
+		}
+	}
+
+	//Stop the timer
+	timer.stop();
+
+	//Return the results
+	return Answer::new(format!("The greatest number of primes found is {}\nIt was found with A = {}, B = {}\nTHe product of A and B is {}", topN, topA, topB, topA * topB), timer.getString());
+}
+
+/* Results:
+The greatest number of primes found is 70
+It was found with A = -61, B = 971
+THe product of A and B is -59231
+It took 2.100 seconds to solve this problem
+*/

src/main.rs

@@ -33,9 +33,9 @@ mod Problems;
 #[derive(PartialEq)]
 enum Selections{EMPTY, SOLVE, DESCRIPTION, LIST, EXIT, SIZE}
 
-static problemNumbers: [u32; 27] = [ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,
+static problemNumbers: [u32; 28] = [ 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];
+									20, 21, 22, 23, 24, 25, 26, 27];
 
 fn main(){
 	let mut selection = Selections::EMPTY;
@@ -236,6 +236,10 @@ fn solveProblem(problemNumber: u32){
 		println!("{}", Problems::Problem26::getDescription());
 		println!("{}", Problems::Problem26::solve());
 	}
+	else if(problemNumber == 27){
+		println!("{}", Problems::Problem27::getDescription());
+		println!("{}", Problems::Problem27::solve());
+	}
 }
 fn descriptionMenu(){
 	//Give some extra space to print the description
@@ -339,6 +343,9 @@ fn printDescription(problemNumber: u32){
 	else if(problemNumber == 26){
 		println!("{}", Problems::Problem26::getDescription());
 	}
+	else if(problemNumber == 27){
+		println!("{}", Problems::Problem27::getDescription());
+	}
 }
 fn getProblemNumber() -> u32{
 	println!("Enter a problem number: ");