FindBall.cs

//https://leetcode.com/problems/where-will-the-ball-fall/

namespace LeetCode.Problems;

public sealed class FindBall : ProblemBase
{
    [Theory]
    [ClassData(typeof(FindBall))]
    public override void Test(object[] data) => base.Test(data);

    protected override void AddTestCases()
        => Add(it => it.Param2dArray("[[1,1,1,-1,-1],[1,1,1,-1,-1],[-1,-1,-1,1,1],[1,1,1,1,-1],[-1,-1,-1,-1,-1]]").ResultArray("[1,-1,-1,-1,-1]"))
             .Add(it => it.Param2dArray("[[1,1,1,1,1,1],[-1,-1,-1,-1,-1,-1],[1,1,1,1,1,1],[-1,-1,-1,-1,-1,-1]]").ResultArray("[0,1,2,3,4,-1]"))
             .Add(it => it.Param2dArray("[[-1]]").ResultArray("[-1]"));

    private int[] Solution(int[][] grid)
    {
        var width = grid[0].Length;
        var balls = Enumerable.Range(0, grid[0].Length).ToArray();

        for (var y = 0; y < grid.Length; y++)
        {
            for (var b = 0; b < width; b++)
            {
                if (balls[b] == -1)
                {
                    continue;
                }

                var x = balls[b];
                if (grid[y][x] == 1)
                {
                    if (x + 1 == width || grid[y][x + 1] == -1)
                    {
                        balls[b] = -1;
                    }
                    else
                    {
                        balls[b] = x + 1;
                    }
                }
                else if (grid[y][x] == -1)
                {
                    if (x - 1 < 0 || grid[y][x - 1] == 1)
                    {
                        balls[b] = -1;
                    }
                    else
                    {
                        balls[b] = x - 1;
                    }
                }
            }
        }

        return balls;
    }
}