You avoid the ropes, plunge into the river, and swim to shore.

The Elves yell something about meeting back up with them upriver, but the river is too loud to tell exactly what they're saying. They finish crossing the bridge and disappear from view.

Read the full puzzle.

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

namespace AdventOfCode.Y2022.Day10;

[ProblemName("Cathode-Ray Tube")]
class Solution : Solver {

    public object PartOne(string input) {
        var sample = new[] { 20, 60, 100, 140, 180, 220 };
        return Signal(input)
            .Where(signal => sample.Contains(signal.cycle))
            .Select(signal => signal.x * signal.cycle)
            .Sum();
    }

    public object PartTwo(string input) => 
        Signal(input)
            .Select(signal => {
                var spriteMiddle = signal.x;
                var screenColumn = (signal.cycle - 1) % 40;
                return Math.Abs(spriteMiddle - screenColumn) < 2 ? '#' : ' ';
            })
            .Chunk(40)
            .Select(line => new string(line))
            .Aggregate("", (screen, line) => screen + line + "\n")
            .Ocr();

    IEnumerable<(int cycle, int x)> Signal(string input) {
        var (cycle, x) = (1, 1);
        foreach (var line in input.Split("\n")) {
            var parts = line.Split(" ");
            switch (parts[0]) {
                case "noop":
                    yield return (cycle++, x);
                    break;
                case "addx":
                    yield return (cycle++, x);
                    yield return (cycle++, x);
                    x += int.Parse(parts[1]);
                    break;
                default:
                    throw new ArgumentException(parts[0]);
            }
        }
    }
}

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