Package net.n1da.dev.euler

Class PE0027

java.lang.Object

net.n1da.dev.euler.core.Problem

net.n1da.dev.euler.PE0027

All Implemented Interfaces:

Solvable

public class PE0027
extends Problem

Solution for problem 27 "Quadratic primes" completed on Thu, 23 Jul 2015, 23:58.

Since:

20.07.2015 23:12:27

Author:

Nico Danneberg

See Also:

Problem @ Project Euler, Solution @ Ni-Da-Net

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.ArrayList<java.lang.Integer>	cache	A memory for all found primes to save some time while checking the result of every calculation.
private java.util.ArrayList<java.lang.Integer>	primes	A storage for all primes less than 1000.

Fields inherited from class net.n1da.dev.euler.core.Problem

number, title

Constructor Summary

Constructors

Constructor	Description
PE0027()	A simple constructor to set number and title.

Method Summary

Modifier and Type	Method	Description
void	prepare()	Initializes the primes and cache memories.
java.lang.String	solve()	This method solves the given problem by running three nested loops.

Methods inherited from class net.n1da.dev.euler.core.Problem

finish, getResult, getRuntime, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

primes

private java.util.ArrayList<java.lang.Integer> primes

A storage for all primes less than 1000.

cache

private java.util.ArrayList<java.lang.Integer> cache

A memory for all found primes to save some time while checking the result of every calculation.

Constructor Detail

PE0027

public PE0027()

A simple constructor to set number and title.

Method Detail

prepare

public void prepare()

Initializes the primes and cache memories. Both have the primes less than 1000 as base. A Sieve is used to get them.

Specified by:

prepare in interface Solvable

Overrides:

prepare in class Problem

See Also:

Sieve

solve

public java.lang.String solve()

This method solves the given problem by running three nested loops. The outer loop steps over all primes and set them as b. A second loop increments a from 1-b to 999. A the inner loop uses the variable n starting by 0 to find the maximum number of primes in a row. Every calculated result is is checked to be a prime or can be found on cache.

Returns:

the product of a and b with the maximum n

See Also:

Mathe.isPrime(int)