自己实现一遍果然感觉不一样
- Python实现单链表
class SingleNode(object):
"""单个节点"""
def __init__(self, item):
# 表元素
self.item = item
# 指向下一节的链接
self.next = None
class SingleLinkList(object):
"""单链表"""
def __init__(self):
# 初始表头部指向None
self._head = None
def is_empty(self):
return self._head == None
def length(self):
count = 0
# 当前项指向表头
cur = self._head
# 当项不为空，向后移动
while cur != None:
count += 1
cur = cur.next
return count
def travel(self):
cur = self._head
while cur != None:
print(cur.item, end='')
cur = cur.next
print('')
def add(self, item):
# 生成单个节点类
node = SingleNode(item)
node.next = self._head
self._head = node
def append(self, item):
node = SingleNode(item)
# 如果链表为空，_head指向新节点
if self.is_empty():
self._head = node
# 否则，循环到链表末尾，指向新节点
else:
cur = self._head
while cur.next != None:
cur = cur.next
cur.next = node
def insert(self, pos, item):
# 插入位置小于0
if pos <= 0:
self.add(item)
# 位置超出末位
elif pos > (self.length()-1):
self.append(item)
# 其他
else:
node = SingleNode(item)
pre = self._head # pre 为 pos-1 位置的节点
count = 0
while count < (pos-1):
count += 1
pre = pre.next
node.next = pre.next
pre.next = node
def remove(self, item):
node = SingleNode(item)
cur = self._head
pre = None
while cur != None:
# 如果找到指定元素
if cur.item == node.item:
if not pre:
# 第一个节点相同，即删除头节点
self._head = node.next
else:
pre.next = cur.next
break
# 否则，按链表后移节点
else:
pre = cur
cur = cur.next
def search(self, item):
"""查找元素是否存在，返回True/False"""
node = SingleNode(item)
cur = self._head
while cur != None:
if cur.item == node.item:
return True
cur = cur.next
return False
def main():
link_list = SingleLinkList()
print(link_list.is_empty())
link_list.add(1)
link_list.add(4)
link_list.insert(0, 2)
link_list.append(3)
print('是否有1: ', link_list.search(1))
link_list.travel()
print('长度: ', link_list.length())
link_list.remove(1)
link_list.travel()
if __name__ == '__main__':
main()
- Python实现单项循环链表
class SingleNode(object):
"""单节点"""
def __init__(self, item):
self.item = item
self.next = None
class SinCycLinkedlist(object):
"""单项循环链表"""
def __init__(self):
self._head = None
def is_empty(self):
return self._head == None
def length(self):
# 头部为空
if self.is_empty():
count = 0
else:
# 循环直到 next 不指向头部
count = 1
cur = self._head
while cur.next != self._head:
count += 1
cur = cur.next
return count
def travel(self):
if self.is_empty():
return
cur = self._head
print(cur.item, end=' ')
while cur.next != self._head:
cur = cur.next
print(cur.item, end=' ')
print('')
def add(self, item):
node = SingleNode(item)
# 空链表
if self.is_empty():
self._head = node
node.next = node
else:
node.next = self._head
# 将链表末尾指向新节点
cur = self._head
while cur.next != self._head:
cur = cur.next
cur.next = node
self._head = node
def append(self, item):
node = SingleNode(item)
# 空链表
if self.is_empty():
self._head = node
node.next = node
else:
# 链表末尾指向新节点，新节点指向表头
cur = self._head
while cur.next != self._head:
cur = cur.next
cur.next = node
node.next = self._head
def remove(self, item):
cur = self._head
pre = None
# 链表为空
if self.is_empty():
return
# 移除的首项
if item == self._head.item:
# 链表只有一项
if self.length() == 1:
self._head = None
# 头部和尾部 指向移除项的next,
else:
while cur.next != self._head:
cur = cur.next
cur.next = self._head.next
self._head = self._head.next
else:
pre = self._head
while cur.next != self._head:
if cur.item == item:
pre.next = cur.next
return
pre = cur
cur = cur.next
# 删除的尾项
if cur.item == item:
pre.next = self._head
def insert(self, pos, item):
# 超出链表项
if pos >= self.length():
self.append(item)
# 插在头部
elif pos <= 0:
self.add(item)
# 中间位置
else:
node = SingleNode(item)
cur = self._head
count = 0
while count < (pos-1):
count += 1
cur = cur.next
node.next = cur.next
cur.next = node
def search(self, item):
if self.is_empty():
return False
cur = self._head
if item == cur.item:
return True
while cur.next != self._head:
cur = cur.next
if cur.item == item:
return True
return False
def main():
li = SinCycLinkedlist()
print(li.is_empty())
li.add(1)
li.add(23)
li.append(4)
li.travel()
li.remove(4)
li.remove(56)
li.travel()
li.insert(0, 11)
li.insert(2, 5)
li.insert(6, 8)
li.travel()
print(li.length())
print(li.search(9))
print(li.search(5))
if __name__ == '__main__':
main()
- Python实现双向链表
class Node(object):
def __init__(self, item):
self.item = item
self.next = None
self.prev = None
class DLinkList(object):
def __init__(self):
self._head = None
def is_empty(self):
return self._head == None
def length(self):
count = 0
cur = self._head
while cur != None:
cur = cur.next
count += 1
return count
def travel(self):
# 空链表
cur = self._head
while cur != None:
print(cur.item, end=' ')
cur = cur.next
print('')
def add(self, item):
node = Node(item)
# 空链表
if self.is_empty():
self._head = node
else:
node.next = self._head
self._head.prev = node
self._head = node
def append(self, item):
node = Node(item)
# 空链表
if self.is_empty():
self._head = node
else:
cur = self._head
while cur.next != None:
cur = cur.next
cur.next = node
node.prev = cur
def insert(self, pos, item):
# 位置小于0
if pos <= 0:
self.add(item)
# 位置大于末位
elif pos >= self.length():
self.append(item)
# 位置在中间
else:
cur = self._head
count = 0
while count < (pos-1):
cur = cur.next
count += 1
node = Node(item)
node.next = cur.next
node.prev = cur
cur.next.prev = node
cur.next = node
def remove(self, item):
# 空链表
if self.is_empty():
return
else:
cur = self._head
# 删除的是首项
if cur.item == item:
# 链表仅有一项
if cur.next == None:
self._head = None
# 链表不止一项
else:
cur.next.prev = None
self._head = cur.next
return
# 删除的是中间项
while cur != None:
if cur.item == item:
cur.next.prev = cur.prev
cur.prev.next = cur.next
break
cur = cur.next
def search(self, item):
cur = self._head
while cur != None:
if cur.item == item:
return True
cur = cur.next
return False
if __name__ == '__main__':
li = DLinkList()
print('是否是空链表:', li.is_empty())
li.append(9)
li.append(10)
li.add(8)
li.add(5)
li.insert(-1, 6)
li.travel()
li.remove(6)
li.travel()
print('length:', li.length())
print('是否有99:', li.search(99))
print('是否有8:', li.search(8))
