Update spiral_print.py

matrix/spiral_print.py

@@ -76,7 +76,56 @@ def spiral_print_clockwise(a: list[list[int]]) -> None:
         return
 
 
+# Other Easy to understand Approach
+
+
+def spiral_traversal(matrix: list[list]) -> 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([])
+    """
+    if matrix:
+        return list(matrix.pop(0)) + spiral_traversal(list(zip(*matrix))[::-1])
+    else:
+        return []
+
+
 # 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)