54-Spiral-Matrix.py

class Solution:
    def spiralOrder(self, matrix: List[List[int]]) -> List[int]:
        if not matrix:
            return []
        row = len(matrix)
        col = len(matrix[0])
        left = 0
        right = col - 1
        top = 0
        bottom = row - 1
        res = []
        while left <= right and top <= bottom:
            for i in range(left, right + 1):
                res.append(matrix[top][i])
            top += 1
            for i in range(top, bottom + 1):
                res.append(matrix[i][right])
            right -= 1
            if top <= bottom:
                for i in range(right, left - 1, -1):
                    res.append(matrix[bottom][i])
                bottom -= 1
            if left <= right:
                for i in range(bottom, top - 1, -1):
                    res.append(matrix[i][left])
                left += 1
        return res