Candy Crush

vector<vector<int>> candyCrush(vector<vector<int>>& board) {

        int rows = board.size(), cols = board[0].size();
        bool no_stable = false;

        for (int i = 0; i < rows; i++)
        {
            for (int j = 0; j + 2 < cols; j++)
            {
                int &v1 = board[i][j];
                int &v2 = board[i][j+1];
                int &v3 = board[i][j+2];

                int v0 = abs(v1);

                if (v0 && v0 == abs(v2) && v0 == abs(v3))
                {
                    v1 = v2 = v3 = - v0;
                    no_stable =  true;
                }
            }
        }

        for (int i = 0; i + 2 < rows; i++)
        {
            for (int j = 0; j < cols; j++)
            {
                int &v1 = board[i][j];
                int &v2 = board[i+1][j];
                int &v3 = board[i+2][j];
                int v0 = std::abs(v1);
                if (v0 && v0 == abs(v2) && v0 == abs(v3))
                {
                    v1 = v2 = v3 = -v0;
                    no_stable = true;
                }
            }
        }

        for (int j = 0; j < cols; j++)
        {
            int fall = rows - 1;
            for (int i = rows - 1; i >= 0; i--)
            {
                if (board[i][j] >= 0)
                {
                    board[fall--][j] = board[i][j];
                }
            }

            for (int i = fall; i >= 0; i--)
            {
                board[i][j] = 0;
            }
        }

        return no_stable ? candyCrush(board) : board;
    }