Add queue-implementation-using-two-stacks.py (OmkarPathak#18)

Author: Shane Creedon

Stack/P05_QueueImplementationUsingTwoStacks.py

@@ -0,0 +1,49 @@
+class StackedQueue:
+
+    def __init__(self):
+        self.stack = Stack()
+        self.alternateStack = Stack()
+
+    def enqueue(self, item):
+        while(not self.stack.is_empty()):
+            self.alternateStack.push(self.stack.pop())
+
+        self.alternateStack.push(item)
+
+        while(not self.alternateStack.is_empty()):
+            self.stack.push(self.alternateStack.pop())
+    
+    def dequeue(self):
+        return self.stack.pop()
+
+    def __repr__(self):
+        return repr(self.stack)
+
+class Stack:
+    def __init__(self):
+        self.items = []
+
+    def push(self, item):
+        self.items.append(item)
+
+    def pop(self):
+        return self.items.pop()
+
+    def size(self):
+        return len(self.items)
+
+    def is_empty(self):
+        return self.items == []
+
+    def __repr__(self):
+        return str(self.items)
+
+if __name__ == "__main__":
+    structure = StackedQueue()
+    structure.enqueue(4)
+    structure.enqueue(3)
+    structure.enqueue(2)
+    structure.enqueue(1)
+    print(structure)
+    structure.dequeue()
+    print(structure)