C# (CSharp) UtilityMath.ErathostenesSieve示例

示例#1

        public PrimeSet(int c)
        {
            Count    = c;
            Primes   = UtilityMath.ErathostenesSieve(3, 20000);
            Minimums = Enumerable.Repeat(int.MaxValue, 5).ToArray();
            Pairs    = new HashSet <int> [Primes.Length];
            Set      = new int[Count];

            var IsPrime = UtilityMath.IsPrimeUsingSquares.Memoize();

            for (int a = 0; a < Primes.Length; a++)
            {
                Pairs[a] = new HashSet <int>();
                int x = Primes[a];

                for (int b = 0; b < Primes.Length; b++)
                {
                    if (a == b)
                    {
                        continue;
                    }
                    int y = Primes[b];
                    if (IsPrime(UtilityMath.NumericConcat(x, y)) &&
                        IsPrime(UtilityMath.NumericConcat(y, x)))
                    {
                        Pairs[a].Add(y);
                    }
                }
            }
        }