"""
54. Spiral Matrix
Difficulty: Medium
https://leetcode.com/problems/spiral-matrix/

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Given an m x n matrix, return all elements of the matrix in spiral
order.



Example 1:

Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [1,2,3,6,9,8,7,4,5]

Example 2:

Input: matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
Output: [1,2,3,4,8,12,11,10,9,5,6,7]



Constraints:

        • m == matrix.length

        • n == matrix[i].length

        • 1 <= m, n <= 10

        • -100 <= matrix[i][j] <= 100
"""


class Solution:
    def spiralOrder(self, matrix: List[List[int]]) -> List[int]:
        res = []
        top, bottom = 0, len(matrix) - 1
        left, right = 0, len(matrix[0]) - 1

        while top <= bottom and left <= right:
            # 1. Top Row
            for c in range(left, right + 1):
                res.append(matrix[top][c])
            top += 1

            # 2. Right Column
            for r in range(top, bottom + 1):
                res.append(matrix[r][right])
            right -= 1

            # 3. Bottom Row
            if top <= bottom:
                for c in range(right, left - 1, -1):
                    res.append(matrix[bottom][c])
                bottom -= 1

            # 4. Left Column
            if left <= right:
                for r in range(bottom, top - 1, -1):
                    res.append(matrix[r][left])
                left += 1

        return res