Update and rename stack_II.py to stack.py

stacks/stack.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
+
+class Stack:
+
+    def __init__(self):
+        self.stack = []
+        self.min = None
+
+    def push(self, val: int) -> None:
+        self.stack.append((val, self.min))
+        if self.min is not None:
+            self.min = min(self.min, val)
+        else:
+            self.min = val
+
+    def pop(self) -> None:
+        if self.stack:
+            (val, prior_min) = self.stack.pop()
+            self.min = prior_min
+            return val
+        
+    def top(self) -> int:
+        if self.stack:
+            return self.stack[-1][0]
+
+    def get_min(self) -> int:
+        return self.min
+