LeetCode_641.py

"""
设计实现双端队列。

实现 MyCircularDeque 类:

MyCircularDeque(int k)：构造函数,双端队列最大为 k 。
boolean insertFront()：将一个元素添加到双端队列头部。 如果操作成功返回 true，否则返回 false 。
boolean insertLast()：将一个元素添加到双端队列尾部。如果操作成功返回 true，否则返回 false 。
boolean deleteFront()：从双端队列头部删除一个元素。 如果操作成功返回 true，否则返回 false 。
boolean deleteLast()：从双端队列尾部删除一个元素。如果操作成功返回 true，否则返回 false 。
int getFront())：从双端队列头部获得一个元素。如果双端队列为空，返回 -1。
int getRear()：获得双端队列的最后一个元素。如果双端队列为空，返回 -1 。
boolean isEmpty()：若双端队列为空，则返回true，否则返回 false 。
boolean isFull()：若双端队列满了，则返回true，否则返回 false 。

"""


class MyCircularDeque:

    def __init__(self, k: int):
        """
        Initialize your data structure here. Set the size of the deque to be k.
        """
        self.capacity = k + 1
        self.deque = [0] * self.capacity
        self.front = 0
        self.rear = 0

    def insertFront(self, value: int) -> bool:
        """
        Adds an item at the front of Deque. Return true if the operation is successful.
        """
        if self.isFull():
            return False
        self.front = (self.front - 1 + self.capacity) % self.capacity
        self.deque[self.front] = value
        return True

    def insertLast(self, value: int) -> bool:
        """
        Adds an item at the rear of Deque. Return true if the operation is successful.
        """
        if self.isFull():
            return False
        self.deque[self.rear] = value
        self.rear = (self.rear + 1) % self.capacity
        return True

    def deleteFront(self) -> bool:
        """
        Deletes an item from the front of Deque. Return true if the operation is successful.
        """
        if self.isEmpty():
            return False
        self.front = (self.front + 1) % self.capacity
        return True

    def deleteLast(self) -> bool:
        """
        Deletes an item from the rear of Deque. Return true if the operation is successful.
        """
        if self.isEmpty():
            return False
        self.rear = (self.rear - 1 + self.capacity) % self.capacity
        return True

    def getFront(self) -> int:
        """
        Get the front item from the deque.
        """
        if self.isEmpty():
            return -1
        return self.deque[self.front]

    def getRear(self) -> int:
        """
        Get the last item from the deque.
        """
        if self.isEmpty():
            return -1
        return self.deque[(self.rear - 1 + self.capacity) % self.capacity]

    def isEmpty(self) -> bool:
        """
        Checks whether the circular deque is empty or not.
        """
        return self.front == self.rear

    def isFull(self) -> bool:
        """
        Checks whether the circular deque is full or not.
        """
        return (self.rear + 1) % self.capacity == self.front




if __name__ == '__main__':
    circularDeque = MyCircularDeque(3)
    print(circularDeque.insertLast(1))
    print(circularDeque.insertLast(2))
    print(circularDeque.insertFront(3))
    print(circularDeque.insertFront(4))
    print(circularDeque.getRear())
    print(circularDeque.isFull())
    print(circularDeque.deleteLast())
    print(circularDeque.insertFront(4))
    print(circularDeque.getFront())