栈，队列，双端队列的实现(Python)

栈的实现

# 栈，先进后出,push/pop 复杂度为O(1)
# List的尾端作为栈顶
class Stack:
    def __init__(self):
        self.items = []

    def isEmpty(self):
        return self.items == []

    def push(self, item):
        self.items.append(item)

    def pop(self):
        return self.items.pop()

    def peek(self):
        return self.items[len(self.items) - 1]

    def size(self):
        return len(self.items)

队列的实现

# 队列，先进先出,
# List首端作为队列尾端，List的末端作为队列首端
# enqueue()复杂度为O(n),dequeue()复杂度为O(1)
class Queue:
    def __init__(self):
        self.items = []

    def isEmpty(self):
        return self.items == []

    def enqueue(self, item):
        self.items.insert(0, item)

    def dequeue(self):
        return self.items.pop()

    def size(self):
        return len(self.items)

双端队列的实现

# 双端队列，跟队列相似，但数据的增删既可以从首端进行也可以从尾端进行
# List下标0作为deque的尾端，下标-1作为deque的首端
class Deque:
    def __init__(self):
        self.items = []

    def isEmpty(self):
        return self.items == []

    def addFront(self, item):
        self.items.append(item)

    def addRear(self, item):
        self.items.insert(0, item)

    def removeFront(self):
        self.items.pop()

    def removeRear(self):
        self.items.pop(0)

    def size(self):
        return len(self.items)

调用示例：

s = Stack()
print(s.isEmpty())
s.push(4)
s.push('sunday')
print(s.peek())
s.push(True)
print(s.size())
print(s.isEmpty())
s.push(8.4)
s.pop()
s.pop()
print(s.size())

Output:
True
sunday
3
False
2