ProjectEulerTS/Problems/Problem37.ts

//ProjectEulerTS/Problems/Problem37.ts
//Matthew Ellison
// Created: 07-01-21
//Modified: 07-14-21
//Find the sum of the only eleven primes that are both truncatable from left to right and right to left (2, 3, 5, and 7 are not counted).
//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 { getSum } from "../../../Typescript/typescriptClasses/ArrayAlgorithms";
import { isPrime, sieveOfEratosthenes } from "../../../Typescript/typescriptClasses/NumberAlgorithms";
import { Unsolved } from "../Unsolved";
import { Problem } from "./Problem";


export class Problem37 extends Problem{
	//Variables
	//Static variables
	private static LAST_PRIME_BEFORE_CHECK: number = 7;	//The last prime before 11 since signle digit primes aren't checked
	//Instance variables
	private truncPrimes: number[];
	private sum: number;

	//Functions
	//Constructor
	public constructor(){
		super("Find the sum of the only eleven primes that are both truncatable from left to right and right to left (2, 3, 5, and 7 are not counted).");
		this.truncPrimes = [];
		this.sum = 0;
	}
	//Operational functions
	//Solve the problems
	public solve(): void{
		//If the porblem has already been solved do nothing and end the function
		if(this.solved){
			return;
		}

		//Start the timer
		this.timer.start();


		//Create the sieve and get the first prime number
		let sieve = sieveOfEratosthenes();
		let tempPrime = sieve.next().value;
		let currentPrime: number = 0;
		if(typeof tempPrime == "number"){
			currentPrime = tempPrime;
		}
		else{
			throw new Unsolved("Sieve overflowed")
		}
		while(currentPrime < Problem37.LAST_PRIME_BEFORE_CHECK){
			tempPrime = sieve.next().value;
			if(typeof tempPrime == "number"){
				currentPrime = tempPrime;
			}
			else{
				throw new Unsolved("Sieve overflowed")
			}
		}
		//Loop until truncPrimes contains 11 elements
		while(this.truncPrimes.length < 11){
			let isTruncPrime: boolean = true;
			//Get the next prime
			tempPrime = sieve.next().value;
			if(typeof tempPrime == "number"){
				currentPrime = tempPrime;
			}
			else{
				throw new Unsolved("Sieve overflowed")
			}
			//Conver the prime to a string
			let primeString: string = currentPrime.toString();
			//If the string contains an even digit move to the next prime
			for(let strLoc = 0;(strLoc < primeString.length) && (primeString[strLoc] == '2');++strLoc){
				//Allow 2 to be the first digit
				if((strLoc == 0) && (primeString[strLoc] == '2')){
					continue;
				}
				if((primeString[strLoc] == '0') || (primeString[strLoc] == '2') || (primeString[strLoc] == '4') || (primeString[strLoc] == '6') || (primeString[strLoc] == '8')){
					isTruncPrime = false;
					break;
				}
			}
			//Start removing digits from the left and see if the number stays prime
			if(isTruncPrime){
				for(let truncLoc = 1;(truncLoc < primeString.length) && (isTruncPrime);++truncLoc){
					//Create a substring of the prime, removing the needed digits from the left
					let primeSubstring: string = primeString.substring(truncLoc);
					//Convert the string to an int and see if the number is still prime
					let newPrime: number = parseInt(primeSubstring);
					if(!isPrime(newPrime)){
						isTruncPrime = false;
					}
				}
			}
			//Start removing digits from the right and see if the number stays prime
			if(isTruncPrime){
				for(let truncLoc = 1;(truncLoc < primeString.length) && (isTruncPrime);++truncLoc){
					//Create a substring of the prime, removing the needed digits from the right
					let primeSubstring: string = primeString.substring(0, primeString.length - truncLoc);
					//Convert the string to an int and see if the number is still prime
					let newPrime: number = parseInt(primeSubstring);
					if(!isPrime(newPrime)){
						isTruncPrime = false;
					}
				}
			}
			//If the number remained prime through all operations add it to the vector
			if(isTruncPrime){
				this.truncPrimes.push(currentPrime);
			}
		}
		//Get the sum of all elements in the truncPrimes list
		this.sum = getSum(this.truncPrimes);


		//Stop the timer
		this.timer.stop();

		//Throw a flag to show the problem is solved
		this.solved = true;
	}
	//Reset the problem so it can be run again
	public reset(): void{
		super.reset();
		this.truncPrimes = [];
		this.sum = 0;
	}
	//Gets
	//Returns a string with the solution to the problem
	public getResult(): string{
		this.solvedCheck("result");
		return `The sum of all left and right truncatable primes is ${this.sum}`;
	}
	//Returns the list of primes that can be truncated
	public getTruncatablePrimes(): number[]{
		this.solvedCheck("list of truncatable primes");
		return this.truncPrimes;
	}
	//Returns the sum of all elements in truncPrimes
	public getSumOfTruncatablePrimes(): number{
		this.solvedCheck("sum of truncatable primes");
		return this.sum;
	}
}


/* Results:
The sum of all left and right truncatable primes is 748317
It took an average of 104.007 milliseconds to run this problem through 100 iterations
*/