You receive a signal directly from the CPU. Because of your recent assistance with jump instructions, it would like you to compute the result of a series of unusual register instructions.

Each instruction consists of several parts: the register to modify, whether to increase or decrease that register's value, the amount by which to increase or decrease it, and a condition. If the condition fails, skip the instruction without modifying the register. The registers all start at 0. The instructions look like this:

Read the full puzzle.

using System;
using System.Collections.Generic;
using System.Linq;

namespace AdventOfCode.Y2017.Day08;

[ProblemName("I Heard You Like Registers")]
class Solution : Solver {
 
    public object PartOne(string input) => Run(input).lastMax;
    public object PartTwo(string input) => Run(input).runningMax;

    (int runningMax, int lastMax) Run(string input) {
        var regs = new Dictionary<string, int>();
        var runningMax = 0;
        foreach (var line in input.Split('\n')) {
            //hsv inc 472 if hsv >= 4637
            var words = line.Split(' ');
            var (regDst, op, num, regCond, cond, condNum) = (words[0], words[1], int.Parse(words[2]), words[4], words[5], int.Parse(words[6]));
            if (!regs.ContainsKey(regDst)) {
                regs[regDst] = 0;
            }
            if (!regs.ContainsKey(regCond)) {
                regs[regCond] = 0;
            }

            var conditionHolds = cond switch {
                ">=" => regs[regCond] >= condNum,
                "<=" => regs[regCond] <= condNum,
                "==" => regs[regCond] == condNum,
                "!=" => regs[regCond] != condNum,
                ">"  => regs[regCond] > condNum,
                "<"  => regs[regCond] < condNum,
                _ => throw new NotImplementedException(cond)
            };
            if (conditionHolds) {
                regs[regDst] += 
                    op == "inc" ? num :
                    op == "dec" ? -num :
                    throw new NotImplementedException(op);
            }
            runningMax = Math.Max(runningMax, regs[regDst]);
        }
        return (runningMax, regs.Values.Max());
    }
}

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