C#•2y ago

❔ Write an Aggregate

public override string SolvePartOne()
        {
            HashSet<House> visited = new HashSet<House>()
            {
                new House(0, 0)
            };

            int x = 0,
                y = 0;

            foreach (char c in Input)
            {
                switch (c)
                {
                    case '^': y++; break;
                    case 'v': y--; break;
                    case '>': x++; break;
                    case '<': x--; break;
                    default:
                        throw new InvalidDataException();
                }

                visited.Add(new House(x, y));
            }

            return visited.Count.ToString();
        }

public override string SolvePartOne()
        {
            HashSet<House> visited = new HashSet<House>()
            {
                new House(0, 0)
            };

            int x = 0,
                y = 0;

            foreach (char c in Input)
            {
                switch (c)
                {
                    case '^': y++; break;
                    case 'v': y--; break;
                    case '>': x++; break;
                    case '<': x--; break;
                    default:
                        throw new InvalidDataException();
                }

                visited.Add(new House(x, y));
            }

            return visited.Count.ToString();
        }

Could I aggregate through Input to archive the same result? I'm learning the linq Aggregate, and just curious if I could archive the same result with an Aggregate?

5 Replies

KKSK＠🌸🎵🌸🎵🌸•2y ago

Yes, you could use the Aggregate method to achieve the same result as the code you posted. The Aggregate method allows you to perform a calculation on a sequence and return a single result. In this case, you could use it to track the visited houses and return the total number of houses visited. Here's an example of how you could use Aggregate to accomplish this:

public override string SolvePartOne()
{
    // Initialize the set of visited houses with the starting house at (0, 0)
    var visited = new HashSet<House>()
    {
        new House(0, 0)
    };

    // Use Aggregate to track the visited houses
    visited = Input.Aggregate(visited, (houses, direction) =>
    {
        // Update the current position based on the direction
        switch (direction)
        {
            case '^': y++; break;
            case 'v': y--; break;
            case '>': x++; break;
            case '<': x--; break;
            default:
                throw new InvalidDataException();
        }

        // Add the new position to the set of visited houses
        houses.Add(new House(x, y));

        // Return the updated set of visited houses
        return houses;
    });

    // Return the total number of visited houses
    return visited.Count.ToString();
}

public override string SolvePartOne()
{
    // Initialize the set of visited houses with the starting house at (0, 0)
    var visited = new HashSet<House>()
    {
        new House(0, 0)
    };

    // Use Aggregate to track the visited houses
    visited = Input.Aggregate(visited, (houses, direction) =>
    {
        // Update the current position based on the direction
        switch (direction)
        {
            case '^': y++; break;
            case 'v': y--; break;
            case '>': x++; break;
            case '<': x--; break;
            default:
                throw new InvalidDataException();
        }

        // Add the new position to the set of visited houses
        houses.Add(new House(x, y));

        // Return the updated set of visited houses
        return houses;
    });

    // Return the total number of visited houses
    return visited.Count.ToString();
}

As you can see, the Aggregate method allows us to perform the same operations as the code you posted, but with a more concise and functional-style syntax. I hope this helps! Let me know if you have any other questions.

SwaggerLife•2y ago

Can I have multiple parameters here (houses, direction) or is it set? The solution looks wonderful, thanks by the way.

phaseshift•2y ago

It's always two params. The accumulation thing, and the next element

SwaggerLife•2y ago

I see, that's good to know. Thanks

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Write an Aggregate