Create queuewithstacks.py

Author: careermonk

src/chapter05queues/queuewithstacks.py

@@ -0,0 +1,63 @@
+# Copyright (c) Oct 22, 2018 CareerMonk Publications and others.
+# E-Mail           		: [email protected] 
+# Creation Date    		: 2014-01-10 06:15:46 
+# Last modification		: 2008-10-31 
+#               by		: Narasimha Karumanchi 
+# Book Title			: Data Structures And Algorithmic Thinking With Python
+# Warranty         		: This software is provided "as is" without any 
+# 				   warranty; without even the implied warranty of 
+# 				    merchantability or fitness for a particular purpose. 
+
+import random 
+
+class Stack:
+    def __init__(self, C = 5):
+        self.C = C
+        self.array = []
+    def size(self):
+        return len(self.array)
+    def isEmpty(self):
+        return len(self.array) == 0
+    def isFull(self):
+        return len(self.array) == self.C
+    def peek(self):
+        if self.isEmpty():
+            return None
+        return self.array[self.size()-1]
+    def pop(self):
+        if self.isEmpty():
+            print "Underflow"
+            return None
+        data = self.array.pop()
+        return data
+    def push(self, data):
+        if self.isFull():
+            print "Overflow"
+            return
+        self.array.append(data)
+
+class Queue:
+    def __init__(self):
+        self.s1 = Stack()
+        self.s2 = Stack()
+    def enqueue(self, data):
+        self.s1.push(data)
+
+    def dequeue(self):
+		if (not self.s2.isEmpty()):
+			return self.s2.pop()
+		while(not self.s1.isEmpty()):
+			self.s2.push(self.s1.pop())
+		return self.s2.pop()
+
+q = Queue()
+q.enqueue(1)
+q.enqueue(6)
+q.enqueue(8)
+q.enqueue(10)
+q.enqueue(16)
+print q.dequeue()
+print q.dequeue()
+print q.dequeue()
+print q.dequeue()
+print q.dequeue()