Word Boggle

WordBoggle.java

    public String[] wordBoggle(char board[][], String[] dictionary)
    {
        Set<String> doableWords = new HashSet<String>();
        for (String word : dictionary) {
            if (!doableWords.contains(word)) {
                for (int i = 0; i < board.length; i++) {
                    for (int j = 0; j < board[0].length; j++) {
                        if (canMakeWord(i, j, word, 0, board)) {
                            doableWords.add(word);
                        }
                    }
                }                
            }
        }
        String[] results = new String[doableWords.size()];
        int i = 0; 
        for (String word : doableWords) {
            results[i] = word; 
            i++;
        }
        return results;
    }
    
    private boolean canMakeWord(int i, int j, String str, int index, char[][] board) {
        // checks
        if (i < 0 || j < 0 || i == board.length || j == board[0].length) {
            return false;
        }

        if (index == str.length()) {
            return true;
        }
        if (board[i][j] != str.charAt(index) || board[i][j] == '+') {
            return false;
        }
        
        char savedState = board[i][j];
        board[i][j] = '+';
        
        boolean result =
                canMakeWord(i + 1, j, str, index + 1, board) ||    // d
                canMakeWord(i, j + 1, str, index + 1, board) ||    // r
                canMakeWord(i - 1, j, str, index + 1, board) ||    // u 
                canMakeWord(i, j - 1, str, index + 1, board) ||    // l
                canMakeWord(i + 1, j + 1, str, index + 1, board) || // dr
                canMakeWord(i - 1, j + 1, str, index + 1, board) || // ur
                canMakeWord(i + 1, j - 1, str, index + 1, board) || // dl
                canMakeWord(i - 1, j - 1, str, index + 1, board);   // ul
        board[i][j] = savedState;
        
        return result;
    }