[DS+Algo] 003 一维表结构 Python 代码实现
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- 接上一篇
前言
- 本篇共 3 个代码实现
- 严格来说
code1相当于模仿了 Python 的 list 的部分简单功能code2与code3简单实现了“循环单链表”与“双链表”
- 代码比较简单，但它们的行数相比于普通博文又显得有些长，所以单独写一篇
- 其实放到 GitHub 上更合适，我打算积几个再去 push
1. 模仿 Python 的 list 的一些功能
class SingleNode(object):
def __init__(self, item):
self.item = item
self.next = None
class SingleLinkList(object):
def __init__(self):
self._head = None
def is_empty(self):
return self._head is None
def length(self):
cur = self._head
count = 0
while cur is not None:
count += 1
cur = cur.next
return count
def traverse(self):
cur = self._head
while cur:
print(cur.item)
cur = cur.next
return None
def add_first(self, item):
node = SingleNode(item)
node.next = self._head
self._head = node
def append(self, item):
node = SingleNode(item)
if self.is_empty():
self._head = node
else:
cur = self._head
while cur.next:
cur = cur.next
cur.next = node
def insert(self, pos, item):
if pos <= 0:
self.add_first(item)
elif (self.length() - 1) < pos:
self.append(item)
else:
node = SingleNode(item)
count = 0
pre = self._head
while count < (pos - 1):
count += 1
pre = pre.next
node.next = pre.next
pre.next = node
def remove(self, item):
cur = self._head
pre = None
while cur:
if cur.item == item:
if not pre:
self._head = cur.next
else:
pre.next = cur.next
break
else:
pre = cur
cur = cur.next
def search(self, item):
cur = self._head
while cur:
if cur.item == item:
return True
cur = cur.next
return False
if __name__ == "__main__":
lst = SingleLinkList()
lst.add_first(10)
lst.add_first(20)
lst.append(30)
lst.insert(2, 40)
print(f"Length of lst is {lst.length()}")
lst.traverse()
print(lst.search(30))
print(lst.search(31))
lst.remove(20)
print(f"Length of lst is {lst.length()}")
lst.traverse()2. 循环单链表
class SingleNode(object):
def __init__(self, item):
self.item = item
self.next = None
class SingleCycLinkedList(object):
def __init__(self):
self._head = None
def is_empty(self):
return self._head is None
def length(self):
if self.is_empty():
return 0
cnt = 1
cur = self._head
while cur.next != self._head:
cur = cur.next
cnt += 1
return cnt
def traverse(self):
if self.is_empty():
return
cur = self._head
print(cur.item)
while cur.next != self._head:
cur = cur.next
print(cur.item)
def add_first(self, item):
node = SingleNode(item)
if self.is_empty():
self._head = node
node.next = self._head
else:
node.next = self._head
cur = self._head
while cur.next != self._head:
cur = cur.next
cur.next = node
self._head = node
def append(self, item):
node = SingleNode(item)
if self.is_empty():
self._head = node
node.next = self._head
else:
cur = self._head
while cur.next != self._head:
cur = cur.next
cur.next = node
node.next = self._head
def insert(self, pos, item):
if pos <= 0:
self.add_first(item)
elif self.length() - 1 < pos:
self.append(item)
else:
node = SingleNode(item)
cur = self._head
cnt = 0
while cnt < pos - 1:
cur = cur.next
cnt += 1
node.next = cur.next
cur.next = node
def remove(self, item):
if self.is_empty():
return
cur = self._head
pre = None
if cur.item == item:
if cur.next != self._head:
while cur.next != self._head:
cur = cur.next
cur.next = self._head.next
self._head = self._head.next
else:
self._head = None
else:
pre = self._head
while cur.next != self._head:
if cur.item == item:
pre.next = cur.next
return
else:
pre = cur
cur = cur.next
if cur.item == item:
pre.next = cur.next
def search(self, item):
if self.is_empty():
return False
cur = self._head
if cur.item == item:
return True
while cur.next != self._head:
cur = cur.next
if cur.item == item:
return True
return False
if __name__ == "__main__":
lst = SingleCycLinkedList()
lst.add_first(2)
lst.add_first(1)
lst.append(4)
lst.append(5)
lst.insert(0, 0)
lst.insert(3, 33)
print(f"length: {lst.length()}")
lst.traverse()
print(lst.search(3))
print(lst.search(5))
lst.remove(33)
print(f"length: {lst.length()}")
lst.traverse()3. 双链表
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 is None
def length(self):
cur = self._head
cnt = 0
while cur:
cnt += 1
cur = cur.next
return cnt
def traverse(self):
cur = self._head
while cur:
print(cur.item)
cur = cur.next
def add_first(self, item):
node = Node(item)
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)
if self.is_empty():
self._head = node
else:
cur = self._head
while cur.next:
cur = cur.next
cur.next = node
node.prev = cur
def search(self, item):
cur = self._head
while cur:
if cur.item == item:
return True
cur = cur.next
return False
def insert(self, pos, item):
if pos <= 0:
self.add_first(item)
elif self.length() - 1 < pos:
self.append(item)
else:
node = Node(item)
cur = self._head
cnt = 0
while cnt < pos - 1:
cur = cur.next
cnt += 1
node.prev = cur
node.next = cur.next
cur.next.prev = node
cur.next = node
def remove(self, item):
if self.is_empty():
return
else:
cur = self._head
if cur.item == item:
if cur.next is None:
self._head = None
else:
cur.next.prev = None
self._head = cur.next
return
cur = cur.next
while cur:
if cur.item == item:
cur.prev.next = cur.next
cur.next.prev = cur.prev
break
cur = cur.next
if __name__ == "__main__":
lst = DLinkList()
lst.add_first(2)
lst.add_first(1)
lst.append(4)
lst.append(5)
lst.insert(0, 0)
lst.insert(3, 33)
print(f"length: {lst.length()}")
lst.traverse()
print(lst.search(3))
print(lst.search(5))
lst.remove(33)
print(f"length: {lst.length()}")
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