/// <summary>
/// Recursively goes through a boggle board looking for words.
/// </summary>
/// <param name="currentX">The current x position on the boggle board</param>
/// <param name="currentY">The current y position on the boggle board</param>
/// <param name="boggleBoard">The current boggle board</param>
/// <param name="visitedBoard">The array of bools representing the state of what has been searched</param>
/// <param name="currentNode">The current node in the dictionary</param>
/// <param name="wordList">The list of words that have been found so far</param>
/// <param name="currentWord">the current "word". May not be a valid word at any given time</param>
/// <param name="minWordSize">The minimmum length a word should be before adding it to the list</param>
private static void SearchBoggleBoard(int currentX, int currentY, char[][] boggleBoard, bool[][] visitedBoard, BoggleDictionaryNode currentNode, List <string> wordList, string currentWord, int minWordSize)
{
// We add the current letter to our current "word"
// we also need to mark the current board as having been visited
currentWord += boggleBoard[currentY][currentX];
visitedBoard[currentY][currentX] = true;
if (currentNode.isWord && currentWord.Length >= minWordSize && !wordList.Contains(currentWord))
{
wordList.Add(currentWord);
}
for (int lookX = -1; lookX < 2; lookX++)
{
for (int lookY = -1; lookY < 2; lookY++)
{
int nextX = currentX + lookX;
int nextY = currentY + lookY;
/// We recursively look at other places but we have to make sure
/// we only check for places that we haven't been, that are on the board
/// and that continue a chain in our dictionary
if (nextX >= 0 &&
nextY >= 0 &&
nextY < boggleBoard.Length &&
nextX < boggleBoard[nextY].Length &&
!visitedBoard[nextY][nextX] &&
currentNode.Leaves.ContainsKey(boggleBoard[nextY][nextX]))
{
SearchBoggleBoard(nextX, nextY, boggleBoard, visitedBoard, currentNode.Leaves[boggleBoard[nextY][nextX]], wordList, currentWord, minWordSize);
}
}
}
visitedBoard[currentY][currentX] = false;
}
/// <summary>
/// Finds words within a boggle board of a specified length
/// </summary>
/// <param name="height">The height of the boggle board</param>
/// <param name="width">The width of the boggle board</param>
/// <param name="board">the representation of the boggle board as a two dimensional char array</param>
/// <param name="minWordSize">The smallest size of a word that is desired to be returned</param>
/// <param name="dictionary">THe boggle dictionary object to check against</param>
/// <returns>List of all of the words found</returns>
public static List <string> SolveBoggle(int height, int width, char[][] board, int minWordSize, BoggleDictionaryNode dictionary)
{
if (dictionary == null)
{
throw new System.ArgumentNullException(nameof(dictionary));
}
var visitedBoard = new bool[height][];
for (int x = 0; x < height; x++)
{
visitedBoard[x] = new bool[width];
}
var foundWordList = new List <string>();
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
SearchBoggleBoard(x, y, board, visitedBoard, dictionary.Leaves[char.ToLower(board[y][x])], foundWordList, string.Empty, minWordSize);
}
}
return(foundWordList);
}
