Update spiral_print.py

matrix/spiral_print.py

@@ -7,6 +7,9 @@
 """
 
 
+from typing import List
+
+
 def check_matrix(matrix: list[list[int]]) -> bool:
     # must be
     matrix = [list(row) for row in matrix]
@@ -75,8 +78,67 @@ def spiral_print_clockwise(a: list[list[int]]) -> None:
         print("Not a valid matrix")
         return
 
+# Other Easy to undersatnd Approach
+
+
+def spiral_traversal(matrix: List[List[int]]) -> List[int]:
+    """
+    >>> spiral_traversal([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]])
+    [1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7]
+
+    Example:
+    matrix = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
+
+    Algorithm:
+        Step 1. first pop the 0 index list. (which is [1,2,3,4] and concatenate the
+                output of [step 2])
+        Step 2. Now perform matrix’s Transpose operation (Change rows to column
+                and vice versa) and reverse the resultant matrix.
+        Step 3. Pass the output of [2nd step], to same recursive function till
+                base case hits.
+
+    Dry Run:
+
+    Stage 1.
+    [1, 2, 3, 4] +   spiral_traversal(   [[8, 12 ]
+                                            [7, 11]
+                                            [6, 10]
+                                            [5, 9]]
+                        )
+
+    Stage 2.
+    [1, 2, 3, 4, 8, 12] + spiral_traversal( [[11, 10, 9],
+                                                [7, 6, 5]]
+                            )
+
+    Stage 3.
+    [1, 2, 3, 4, 8, 12, 11, 10, 9] + spiral_traversal(  [[5],
+                                                            [6],
+                                                            [7]
+                                        ])
+
+    Stage 4.
+    [1, 2, 3, 4, 8, 12, 11, 10, 9, 5] + spiral_traversal(  [[5],
+                                                        [6],
+                                                        [7]
+                                    ])
+
+    Stage 5.
+    [1, 2, 3, 4, 8, 12, 11, 10, 9, 5] + spiral_traversal(  [[6, 7]
+                                    ])
+
+    Stage 6.
+    [1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7] + spiral_traversal([])
+
+
+    """
+    return matrix and list(matrix.pop(0)) + spiral_traversal(list(zip(*matrix))[::-1])
+
 
 # driver code
 if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()
     a = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
     spiral_print_clockwise(a)