reorganize stack

Author: danghai

algorithms/stack/__init__.py

@@ -0,0 +1,10 @@
+from .stack import *
+from .is_consecutive import *
+from .is_sorted import *
+from .remove_min import *
+from .stutter import *
+from .switch_pairs import *
+from .valid_parenthesis import *
+from .simplify_path import *
+from .stack import *
+from .ordered_stack import *