AdventOfCode/AdventOfCode.Solutions/2022/Day 11/Day11Part2.cs

using AdventOfCode.Solutions._2022.Day_11;

namespace AdventOfCode.Solutions._2022
{
    public class Day11Part2 : Answerable
    {
        public override int Year { get; set; } = 2022;
        public override int Day { get; set; } = 11;
        public override int Part { get; set; } = 2;

        public override string GetAnswer(byte[] data)
        {
            string[] monkeyString = GetAsString(data).Split(NewLine + NewLine);
            int lowestLcm = 1;
            Monkey[] monkeys = new Monkey[monkeyString.Length];
            
            for (int monkeyIndex = 0; monkeyIndex < monkeys.Length; monkeyIndex++)
            {
                monkeys[monkeyIndex] = new(monkeyIndex, 1, monkeyString[monkeyIndex].Split(NewLine));
                lowestLcm = CalculateLeastCommonMultiple(lowestLcm, monkeys[monkeyIndex].TestDevision);
            }

            for (int monkeyIndex = 0; monkeyIndex < monkeys.Length; monkeyIndex++)
            {
                string[] monkey = monkeyString[monkeyIndex].Split(NewLine);
                int trueMonkey = Convert.ToInt32(monkey[4].Split(' ')[^1]);
                int falseMonkey = Convert.ToInt32(monkey[5].Split(' ')[^1]);

                monkeys[monkeyIndex].SetThrowTargets(monkeys[trueMonkey], monkeys[falseMonkey]);

                monkeys[monkeyIndex].lcm = lowestLcm;
            }

            for (int round = 1; round <= 10_000; round++)
            {
                for (int monkey = 0; monkey < monkeys.Length; monkey++)
                {
                    monkeys[monkey].DoTurn(false);
                }
            }

            long[] mostInspects = monkeys.Select(m => (long)m.TotalInspections).OrderByDescending(i => i).Take(2).ToArray();

            return $"{mostInspects[0] * mostInspects[1]}";
        }

        private int CalculateLeastCommonMultiple(int valueA, int valueB)
        {
            int num1, num2;
            if (valueA > valueB)
            {
                num1 = valueA; num2 = valueB;
            }
            else
            {
                num1 = valueB; num2 = valueA;
            }

            for (int i = 1; i <= num2; i++)
            {
                if ((num1 * i) % num2 == 0)
                {
                    return i * num1;
                }
            }
            return num2;
        }
    }
}