思路：用set记录走过的地方，记下走的方向，根据方向碰壁变换

class Solution:
    def spiralOrder(self, matrix: list[list[int]]) -> list[int]:
        max_rows = len(matrix)
        max_cols = len(matrix[0])
        block_nums = max_cols * max_rows
        count = 1
        i = 0
        j = 0
        answer = [matrix[0][0]]
        direction = 'right'
        visited_block={(0,0)}
        while count < block_nums:
            #print(i, j, count, answer, direction)
            #print(matrix)
            if direction == 'right':
                if j < max_cols - 1 and (i,j+1) not in visited_block:
                    j = j + 1
                    answer.append(matrix[i][j])
                    visited_block.add((i,j))
                    count += 1
                    continue
                else:
                    direction = 'down'

            if direction == 'down':
                if i < max_rows - 1 and (i+1,j) not in visited_block:
                    i += 1
                    answer.append(matrix[i][j])
                    visited_block.add((i, j))
                    count += 1
                    continue
                else:
                    direction = 'left'

            if direction == 'left':
                if j > 0 and (i,j-1) not in visited_block:
                    j -= 1
                    answer.append(matrix[i][j])
                    visited_block.add((i, j))
                    count += 1
                    continue
                else:
                    direction = 'up'

            if direction == 'up':
                if i > 0 and (i-1,j) not in visited_block:
                    i -= 1
                    answer.append(matrix[i][j])
                    visited_block.add((i, j))
                    count += 1
                    continue
                else:
                    direction = 'right'
        #print(answer)
        return answer