数据结构(北大公开课)
线性结构
双端队列
1、双端队列知识框架
2、双端队列的实现
#实现双端队列
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):
return self.items.pop()
def removeRear(self):
return self.items.pop(0)
def size(self):
return len(self.items)
3、双端队列应用——回文词判断
#回文词判定
def palcheck(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(palcheck('lalalaiju'))
print(palcheck('radar'))