54. Spiral Matrix - LeetCode

class Solution:
    def spiralOrder(self, matrix: list[list[int]]) -> list[int]:
        if not matrix or not matrix[0]:
            return []
        result = []
        t, b, l, r = 0, len(matrix) - 1, 0, len(matrix[0]) - 1
        while t <= b and l <= r:
            result.extend([matrix[t][x] for x in range(l, r + 1)])
            result.extend([matrix[x][r] for x in range(t + 1, b + 1)])
            if t < b and l < r:
                result.extend([matrix[b][x] for x in range(r - 1, l, -1)])
                result.extend([matrix[x][l] for x in range(b, t, -1)])
            t, b, l, r = t + 1, b - 1, l + 1, r - 1
        return result