Project Euler/27

Problem Statement

Euler discovered a quadratic formula that would generate primes:

$ n^2 + n + 41 $

for $ 0 \leq n \leq 39 $

Another formula, $ n^2 - 79n + 1601 $, was discovered, that produces 80 primes for consecutive values $ 0 \leq n \leq 79 $

Now consider equadratics of the form

$ n^2 + an + b $

where $ |a| \leq 1000 $, $ |b| \leq 1000 $

Find product of coefficients a, b for the quadratic expression producing the maximum number of primes for consecutive values of n, starting with n = 0

Solution

Solution: https://git.charlesreid1.com/cs/euler/src/branch/master/java/Problem027.java

Implemented 2 nested for loops to search for parameter values by brute force. Keep running track of consecutive number of primes generated, and best a/b. Return them at the end.

This algorithm did not have any trickness, or require any special optimization. Used a standard prime number sieve, nothing special.