Word Search

class Solution {
public:
    bool exist(vector<vector<char>>& board, string word) {
        int rows = board.size();
        int columns = board[0].size();
        if(rows * columns < word.length()) {
            return false;
        }
        for(int i = 0; i < rows; i++) {
            for(int j = 0; j < columns; j++) {
                if(board[i][j] == word[0]) {
                    if(search(board, word, i, j, 0, rows, columns)) {
                        return true;
                    }
                }
            }
        }
        return false;
    }

    bool search(vector<vector<char>>& board, string& word, int i, int j, int current, const int& rows, const int& columns) {
        if(i < 0 || i == rows || j < 0 || j == columns || board[i][j] != word[current]) {
            return false;
        }
        board[i][j] -= 60;
        current += 1;
        if(current == word.length()) {
            return true;
        }
        bool result = search(board, word, i + 1, j, current, rows, columns) 
                || search(board, word, i - 1, j, current, rows, columns) 
                || search(board, word, i, j + 1, current, rows, columns) 
                || search(board, word, i, j - 1, current, rows, columns);
        board[i][j] += 60;
        return result;
    }

};