private void CheckRow(PrimeProcessor processor, int row, int[] primes, int sum)
{
var primeList = processor.PrimeTriplets(row);
for (int i = 0; i < primes.Length; i++)
{
Assert.AreEqual(primeList[i + 1].Prime, primes[i]);
}
var sumPrimeTriplets = processor.SumOfPrimeTriplets(row);
Assert.AreEqual(sumPrimeTriplets, sum);
}
public void PrimeTripletsTest()
{
//Problem 196 Prime triplets projecteuler.net/problem=196
//Build a triangle from all positive integers in the following way:
// 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 31- 32 33 34 35 36
//37- 38 39 40 41- 42 43- 44 45
//46 47- 48 49 50 51 52 53- 54 55
//56 57 58 59- 60 61- 62 63 64 65 66
//Each positive integer has up to eight neighbours in the triangle.
//A set of three primes is called a prime triplet if one of the three primes has the other two as neighbours in the triangle.
//For example, in the second row, the prime numbers 2 and 3 are elements of some prime triplet.
//If row 8 is considered, it contains two primes which are elements of some prime triplet, i.e. 29 and 31.
//If row 9 is considered, it contains only one prime which is an element of some prime triplet: 37.
//Define S(n) as the sum of the primes in row n which are elements of any prime triplet.
//Then S(8)=60 and S(9)=37.
//You are given that S(10000)=950007619.
//Find S(5678027) + S(7208785).
// O( n * n * log(n) )
var processor = new PrimeProcessor();
var primeList = processor.PrimeTriplets(1);
Assert.AreEqual(primeList[1].Prime, 1);
int row = 2; int[] primes = new int[] { 2, 3 }; int sum = 5;
CheckRow(processor, row, primes, sum);
row = 3; primes = new int[] { 5 }; sum = 5;
CheckRow(processor, row, primes, sum);
row = 4; primes = new int[] { 7 }; sum = 7;
CheckRow(processor, row, primes, sum);
row = 5; primes = new int[] { 11, 13 }; sum = 24;
CheckRow(processor, row, primes, sum);
row = 6; primes = new int[] { 17, 19 }; sum = 36;
CheckRow(processor, row, primes, sum);
row = 7; primes = new int[] { 23 }; sum = 23;
CheckRow(processor, row, primes, sum);
row = 8; primes = new int[] { 29, 31 }; sum = 60;
CheckRow(processor, row, primes, sum);
row = 9; primes = new int[] { 37, 41, 43 }; sum = 37;
CheckRow(processor, row, primes, sum);
row = 10; primes = new int[] { 47, 53 }; sum = 47;
CheckRow(processor, row, primes, sum);
row = 11; primes = new int[] { 59, 61 }; sum = 120;
CheckRow(processor, row, primes, sum);
}
