rotate_matrix.py: Add type hints for return values

matrix/rotate_matrix.py

@@ -1,99 +1,76 @@
 # -*- coding: utf-8 -*-
 
 """
-	In this problem, we want to rotate the matrix elements by 90, 180, 270 (counterclockwise)
-	Discussion in stackoverflow: 
-   https://stackoverflow.com/questions/42519/how-do-you-rotate-a-two-dimensional-array
+    In this problem, we want to rotate the matrix elements by 90, 180, 270 (counterclockwise)
+    Discussion in stackoverflow: 
+    https://stackoverflow.com/questions/42519/how-do-you-rotate-a-two-dimensional-array
 """
 
 
-def rotate_90(matrix: [[]]):
+def rotate_90(matrix: [[]]) -> [[]]:
     """
     >>> rotate_90([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]])
     [[4, 8, 12, 16], [3, 7, 11, 15], [2, 6, 10, 14], [1, 5, 9, 13]]
     """
-
-    transpose(matrix)
-    reverse_row(matrix)
-    return matrix
-
 
-def rotate_180(matrix: [[]]):
+    return reverse_row(transpose(matrix))
+
+
+def rotate_180(matrix: [[]]) -> [[]]:
     """
     >>> rotate_180([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]])
     [[16, 15, 14, 13], [12, 11, 10, 9], [8, 7, 6, 5], [4, 3, 2, 1]]
     """
-
-    reverse_column(matrix)
-    reverse_row(matrix)
-
-    """
-    OR
-
-    reverse_row(matrix)
-    reverse_column(matrix)
-    """
-
-    return matrix
 
-
-def rotate_270(matrix: [[]]):
+    return reverse_row(reverse_column(matrix))
+    # OR.. reverse_column(reverse_row(matrix))
+
+
+def rotate_270(matrix: [[]]) -> [[]]:
     """
     >>> rotate_270([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]])
     [[13, 9, 5, 1], [14, 10, 6, 2], [15, 11, 7, 3], [16, 12, 8, 4]]
     """
-
-    transpose(matrix)
-    reverse_column(matrix)
-
-    """
-    OR
-
-    reverse_row(matrix)
-    transpose(matrix)
-    """
-
-    return matrix
+
+    return reverse_column(transpose(matrix))
+    # OR.. transpose(reverse_column(matrix))
 
 
-def transpose(matrix: [[]]):
+def transpose(matrix: [[]]) -> [[]]:
     matrix[:] = [list(x) for x in zip(*matrix)]
     return matrix
-    
-    
-def reverse_row(matrix: [[]]):
+
+
+def reverse_row(matrix: [[]]) -> [[]]:
     matrix[:] = matrix[::-1]
     return matrix
 
 
-def reverse_column(matrix: [[]]):
+def reverse_column(matrix: [[]]) -> [[]]:
     matrix[:] = [x[::-1] for x in matrix]
     return matrix
-    
-    
-def print_matrix(matrix: [[]]):
+
+
+def print_matrix(matrix: [[]]) -> [[]]:
     for i in matrix:
         print(*i)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     matrix = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]]
     print("\norigin:\n")
     print_matrix(matrix)
-    rotate_90(matrix)
     print("\nrotate 90 counterclockwise:\n")
-    print_matrix(matrix)
+    print_matrix(rotate_90(matrix))
 
     matrix = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]]
     print("\norigin:\n")
     print_matrix(matrix)
-    rotate_180(matrix)
     print("\nrotate 180:\n")
-    print_matrix(matrix)
+    print_matrix(rotate_180(matrix))
 
     matrix = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]]
     print("\norigin:\n")
     print_matrix(matrix)
-    rotate_270(matrix)
     print("\nrotate 270 counterclockwise:\n")
-    print_matrix(matrix)
+    print_matrix(rotate_270(matrix))