Merge pull request kelvins#264 from ribmarciojr/dynamic_stack

Add Dynamic Stack in Python

Author: kelvins

README.md

@@ -2288,8 +2288,8 @@ In order to achieve greater coverage and encourage more people to contribute to
                 </a>
             </td>
             <td> <!-- Python -->
-                <a href="./CONTRIBUTING.md">
-                    <img align="center" height="25" src="./logos/github.svg" />
+                <a href="./src/python/dynamic_stack.py">
+                    <img align="center" height="25" src="./logos/python.svg" />
                 </a>
             </td>
             <td> <!-- Go -->

src/python/dynamic_stack.py

@@ -0,0 +1,59 @@
+# Stack: Last In - First Out (LIFO)
+
+
+# Define node format: value and a pointier to next
+class Node:
+    def __init__(self, value: int) -> None:
+        self.value = value
+        self.next = None
+
+
+class DynamicStack:
+    def __init__(self) -> None:
+        self.__first = None
+
+    def isEmpty(self) -> bool:
+        if not self.__first:
+            return True
+        return False
+
+    def push(self, value: int):
+        node = Node(value)
+        node.next = self.__first
+        self.__first = node
+
+    def pop(self) -> int:
+        if self.isEmpty():
+            raise Exception("Stack is empty!")
+        removedElement = self.__first.value
+        self.__first = self.__first.next
+        return removedElement
+
+    def show(self) -> None:
+        node = self.__first
+        print("[", end=" ")
+        while node:
+            print(node.value, end=" ")
+            node = node.next
+        print("]")
+
+
+def main() -> None:
+    dynamic_stack = DynamicStack()
+
+    print(f"Push(1,2,4):")
+    dynamic_stack.push(1)
+    dynamic_stack.push(2)
+    dynamic_stack.push(4)
+
+    dynamic_stack.show()
+
+    print(f"Remove last: {dynamic_stack.pop()}")
+    print(f"Remove last: {dynamic_stack.pop()}")
+    print(f"Remove last: {dynamic_stack.pop()}")
+    print("Empty stack!")
+    dynamic_stack.show()
+
+
+if __name__ == "__main__":
+    main()