Index
Queue Implementation
Queue using Linked List
class ListNode(object):
def __init__(self, x):
self.val = x
self.next = None
class Queue(object):
def __init__(self):
self.head = None
self.tail = None
self.size = 0
def __str__(self):
'''print Queue'''
res = ''
cur = self.head
while cur:
res += str(cur.val)
res += ' '
cur = cur.next
return res
def push(self, val):
node = ListNode(val)
if not self.head:
self.head = self.tail = node
else:
self.tail.next = node
self.tail = node
self.size += 1
def popleft(self):
if not self.head:
return None
pop_val = self.head.val
self.head = self.head.next
if self.head == None:
self.tail = None
self.size -= 1
return pop_val
def peekleft(self):
if self.head:
return self.head.val
return None
def get_size(self):
return self.size
def is_empty(self):
return self.size == 0
