1706. Where Will the Ball Fall

FindBall.cs

public class Solution {
  public int[] FindBall(int[][] grid) {
    var ROWS = grid.Length;
    var COLS = grid[0].Length;
    var result = new int[COLS];
    // [ball_id, ball_pos]
    var balls = new Queue<int[]>();
    
    for(var col = 0; col < COLS; ++col)
      balls.Enqueue(new int[]{ col, col });

    for(var row = 0; row < ROWS && balls.Count > 0; ++row){      
      var sz = balls.Count;
      while(sz > 0){
        var ball = balls.Dequeue();
        var ballId = ball[0];
        var ballColPosition = ball[1];

        var hitLeftWall = grid[row][ballColPosition] == -1 && ballColPosition - 1 < 0;
        var hitRightWall = grid[row][ballColPosition] == 1 && ballColPosition + 1 >= COLS;
        
        if(hitLeftWall || hitRightWall){
          sz--;
          continue;
        }

        var isVFromLeft = grid[row][ballColPosition] == -1 && grid[row][ballColPosition - 1] == 1;
        var isVFromRight = grid[row][ballColPosition] == 1 && grid[row][ballColPosition + 1] == -1;
        if(isVFromLeft || isVFromRight){
          sz--;
          continue;
        }         

        balls.Enqueue(new int[]{ ballId, ballColPosition + grid[row][ballColPosition] });
        sz--;
      }
    }

    for(var i = 0; i < COLS; ++i)
        result[i] = -1;

    while(balls.TryDequeue(out var ball))
      result[ball[0]] = ball[1];
    
    return result;
  }
}