Create design-circular-deque.py

Author: kamyu104

Python/design-circular-deque.py

@@ -0,0 +1,129 @@
+# Time:  O(1)
+# Space: O(k)
+
+# Design your implementation of the circular double-ended queue (deque).
+# Your implementation should support following operations:
+#
+# MyCircularDeque(k): Constructor, set the size of the deque to be k.
+# insertFront(): Adds an item at the front of Deque. Return true if the operation is successful.
+# insertLast(): Adds an item at the rear of Deque. Return true if the operation is successful.
+# deleteFront(): Deletes an item from the front of Deque. Return true if the operation is successful.
+# deleteLast(): Deletes an item from the rear of Deque. Return true if the operation is successful.
+# getFront(): Gets the front item from the Deque. If the deque is empty, return -1.
+# getRear(): Gets the last item from Deque. If the deque is empty, return -1.
+# isEmpty(): Checks whether Deque is empty or not. 
+# isFull(): Checks whether Deque is full or not.
+# Example:
+#
+# MyCircularDeque circularDeque = new MycircularDeque(3); // set the size to be 3
+# circularDeque.insertLast(1);			// return true
+# circularDeque.insertLast(2);			// return true
+# circularDeque.insertFront(3);			// return true
+# circularDeque.insertFront(4);			// return false, the queue is full
+# circularDeque.getRear();  				// return 32
+# circularDeque.isFull();				// return true
+# circularDeque.deleteLast();			// return true
+# circularDeque.insertFront(4);			// return true
+# circularDeque.getFront();				// return 4
+#
+# Note:
+# - All values will be in the range of [1, 1000].
+# - The number of operations will be in the range of [1, 1000].
+# - Please do not use the built-in Deque library.
+
+class MyCircularDeque(object):
+
+    def __init__(self, k):
+        """
+        Initialize your data structure here. Set the size of the deque to be k.
+        :type k: int
+        """
+        self.__start = 0
+        self.__size = 0
+        self.__buffer = [0] * k
+
+    def insertFront(self, value):
+        """
+        Adds an item at the front of Deque. Return true if the operation is successful.
+        :type value: int
+        :rtype: bool
+        """
+        if self.isFull():
+            return False
+        self.__start = (self.__start-1) % len(self.__buffer)
+        self.__buffer[self.__start] = value
+        self.__size += 1
+        return True
+
+    def insertLast(self, value):
+        """
+        Adds an item at the rear of Deque. Return true if the operation is successful.
+        :type value: int
+        :rtype: bool
+        """
+        if self.isFull():
+            return False
+        self.__buffer[(self.__start+self.__size) % len(self.__buffer)] = value
+        self.__size += 1
+        return True
+
+    def deleteFront(self):
+        """
+        Deletes an item from the front of Deque. Return true if the operation is successful.
+        :rtype: bool
+        """
+        if self.isEmpty():
+            return False
+        self.__start = (self.__start+1) % len(self.__buffer)
+        self.__size -= 1
+        return True
+
+    def deleteLast(self):
+        """
+        Deletes an item from the rear of Deque. Return true if the operation is successful.
+        :rtype: bool
+        """
+        if self.isEmpty():
+            return False
+        self.__size -= 1
+        return True
+
+    def getFront(self):
+        """
+        Get the front item from the deque.
+        :rtype: int
+        """
+        return -1 if self.isEmpty() else self.__buffer[self.__start]
+
+    def getRear(self):
+        """
+        Get the last item from the deque.
+        :rtype: int
+        """
+        return -1 if self.isEmpty() else self.__buffer[(self.__start+self.__size-1) % len(self.__buffer)]
+
+    def isEmpty(self):
+        """
+        Checks whether the circular deque is empty or not.
+        :rtype: bool
+        """
+        return self.__size == 0
+
+    def isFull(self):
+        """
+        Checks whether the circular deque is full or not.
+        :rtype: bool
+        """
+        return self.__size == len(self.__buffer)
+
+
+# Your MyCircularDeque object will be instantiated and called as such:
+# obj = MyCircularDeque(k)
+# param_1 = obj.insertFront(value)
+# param_2 = obj.insertLast(value)
+# param_3 = obj.deleteFront()
+# param_4 = obj.deleteLast()
+# param_5 = obj.getFront()
+# param_6 = obj.getRear()
+# param_7 = obj.isEmpty()
+# param_8 = obj.isFull()