80. Spiral Matrix

class Solution:
    def spiralOrder(self, matrix: List[List[int]]) -> List[int]:
        if not matrix:
            return []

        res = []
        height = len(matrix)
        width = len(matrix[0])
        right = width - 1
        bottom = height - 1
        top = left = 0

        while len(res) < (height * width):
            # left to right
            for i in range(left, right + 1):
                res.append(matrix[top][i])

            top += 1

            # top to bottom
            for i in range(top, bottom + 1):
                res.append(matrix[i][right])

            right -= 1

            # right to left
            for i in range(right, left - 1, -1):
                res.append(matrix[bottom][i])

            bottom -= 1

            # bottom to top
            for i in range(bottom, top - 1, -1):
                res.append(matrix[i][left])

            left += 1

        # won't break in middle of loop
        return res[:(height * width)]