AoC# 2024 - Day 4: Ceres Search

It’s Advent of Code time 🎄

Advent of Code is an Advent calendar of small programming puzzles for a variety of skill levels that can be solved in any programming language you like.

Day 4 sees the return of the 5am start 😜

Part 1 ⭐️

I decided on a generic approach, passing in the word we needed to find then creating methods that looked in each of the Cardinal and Ordinal directions, for example:

/// <summary>
/// X ++ && Y --
/// </summary>
private bool WordIsUpForward(string word, int x, int y)
{
    for (var i = 0; i < word.Length; i++)
    {
        // bounds check - can we keep looking in is this direction?
        if (x + i >= _input[y].Length || y - i < 0)
            return false;

        // word/character check - is this our word?
        if (_input[y - i][x + i] != word[i])
            return false;
    }

    return true;
}

Part 2 ⭐️

After a little thought, I figured that finding the middle character of the word as my starting point then re-using 2 of the ordinal direction methods in combination with reversing the word ought to work. Pleasingly, it did.