操作
- Deque() 创建一个空的双端队列
- add_front(item) 从队头加入一个item元素
- add_rear(item) 从队尾加入一个item元素
- remove_front() 从队头删除一个item元素
- remove_rear() 从队尾删除一个item元素
- is_empty() 判断双端队列是否为空
- size() 返回队列的大小
class Deque(object):
"""双端队列"""
def __init__(self):
self.items = [] def is_empty(self):
"""判断队列是否为空"""
return self.items == [] def add_front(self, item):
"""在队头添加元素"""
self.items.insert(0,item) def add_rear(self, item):
"""在队尾添加元素"""
self.items.append(item) def remove_front(self):
"""从队头删除元素"""
return self.items.pop(0) def remove_rear(self):
"""从队尾删除元素"""
return self.items.pop() def size(self):
"""返回队列大小"""
return len(self.items) if __name__ == "__main__":
deque = Deque()
deque.add_front(1)
deque.add_front(2)
deque.add_rear(3)
deque.add_rear(4)
print deque.size()
print deque.remove_front()
print deque.remove_front()
print deque.remove_rear()
print deque.remove_rear()
回文检查问题
from pythonds.basic.deque import Deque def palchecker(aString):
chardeque = Deque() for ch in aString:
chardeque.addRear(ch) stillEqual = True while chardeque.size() > 1 and stillEqual:
first = chardeque.removeFront()
last = chardeque.removeRear()
if first != last:
stillEqual = False return stillEqual print(palchecker("lsdkjfskf"))
print(palchecker("radar"))