Spiral Matrix.py

class Solution:
    def spiralOrder(self, mat: List[List[int]]) -> List[int]:
        ans = []
    
        n = len(mat) # no. of rows
        m = len(mat[0]) # no. of columns
    
        # Initialize the pointers reqd for traversal.
        top = 0
        left = 0
        bottom = n - 1
        right = m - 1
        while (top <= bottom and left <= right):
            # For moving left to right
            for i in range(left, right + 1):
                ans.append(mat[top][i])

            top += 1

            # For moving top to bottom.
            for i in range(top, bottom + 1):
                ans.append(mat[i][right])

            right -= 1

            # For moving right to left.
            if (top <= bottom):
                for i in range(right, left - 1, -1):
                    ans.append(mat[bottom][i])

                bottom -= 1

            # For moving bottom to top.
            if (left <= right):
                for i in range(bottom, top - 1, -1):
                    ans.append(mat[i][left])

                left += 1

        return ans