static public List<Integer> spiralOrder(int[][] matrix) {

		List<Integer> list = new ArrayList<Integer>();

		if (matrix.length == 0 || matrix[0].length == 0)

			return list;

		int left = 0, right = matrix[0].length - 1, up = 0, down = matrix.length - 1;

		while (left <= right && up <= down) {

			for (int i = left; i <= right&&up<=down; i++)

				list.add(matrix[up][i]);

			up++;

			for (int i = up; i <= down&&left<=right; i++)

				list.add(matrix[i][right]);

			right--;

			for (int i = right; i >= left&&up<=down; i--)

				list.add(matrix[down][i]);

			down--;

			for (int i = down; i >= up&&left<=right; i--)

				list.add(matrix[i][left]);

			left++;

		}

		return list;

	}