Example #1
0
        public static void Main()
        {
            WriteLine("Problem 23");

            long answer = Problem23.Solve();

            WriteLine($"answer = {answer}");
        }
Example #2
0
        static void Main(string[] args)
        {
            Problem23 prog = new Problem23();
            BitArray abundantNumbers = new BitArray(28124);
            BitArray test = new BitArray(28124);
            //Console.WriteLine(prog.isPerfectNumber(28));
            //Console.WriteLine(prog.isPerfectNumber(12));
            int sumtotal = 0;

            for (int i = 2; i <= 28123; i++)
            {
                if (prog.isAbundantNumber(i))
                {
                    abundantNumbers[i] = true;
                }
            }
            for (int i = 2; i <= 28123; i++)
            {
                if (abundantNumbers[i])
                {
                    for (int j = 2; j <= 28123; j++)
                    {
                        if (i + j > 28123)
                        {
                            break;
                        }
                        if (abundantNumbers[j])
                        {
                            int sum = i + j;
                            test[sum] = true;
                        }
                    }
                }
            }
            // copy paste got me
            for (int i = 1; i <= 28123; i++)
            {
                if (!test[i])
                {
                    sumtotal += i;
                }
            }
            Console.WriteLine("Answer = " + sumtotal);
            Console.ReadKey();
        }