Water Percolation Algorithm

WaterPercolation.java

package com.radams.play;

import org.junit.Test;

/**
 * @author Rich Adams
 */
public class WaterPercolation
{
  public boolean percolate(int[][] grid)
  {
    int[][] tempGrid = grid.clone();
    for (int topIndex = 0; topIndex < grid[0].length; topIndex++)
    {
      if (checkCell(tempGrid, 0, topIndex))
      {
        return true;
      }
    }
    return false;
  }

  protected boolean checkCell(int[][] grid, int row, int col)
  {
    boolean works;
    if(grid[row][col] == 0)
    {
      works = false;
    }
    else if(row == (grid.length - 1) && grid[row][col] == 1)
    {
      works = true;
    }
    else
    {
      grid[row][col] = 0;
      int left = col - 1;
      int right = col + 1;
      int below = row + 1;

      works = (below < grid.length && checkCell(grid, below, col)) ||
              (left > 0 && checkCell(grid, row, left)) ||
              (right < grid[row].length && checkCell(grid, row, right));
    }

    return works;
  }

  @Test
  public void testPercolate()
  {
    int[][] testGrid = {{1, 0, 1, 1},
                        {1, 1, 0, 1},
                        {0, 0, 0, 0}};

    assert(percolate(testGrid));
  }
}