尾部、方法-Python和数据结构学习 -by小雨
今天朋友几篇文章介绍了改尾部、方法-的文章. 关联文章的地址额,睡不着
第二章的尾部还有个关于写翻转棋的,临时先不写.
面下就是直接上Set和Map了,这里应用的是最简略的方法.也就是外部应用的list
先上Set
不过看上去杂复都很高的.
class Set:
def __init__(self):
self._theElements = list()
def __len__(self):
return len(self._theElements)
def __contains__(self,element):
return element in self._theElements
def add(self,element):
if element not in self:
self._theElements.append(element)
def remove(self,element):
assert element in self,"The element must be in the set"
self._theElements.remove(item)
def __eq__(self,setB):
if len(self) != len(setB):
return False
else:
return self.isSubsetOf(setB)
def isSubsetOf(self,setB):
for element in self:
if element not in setB:
return False
return True
def union(self,setB):
newSet = Set()
newSet._theElements.extend(self._theElements)
for element in setB:
if element not in self:
newSet._theElements.append(element)
return newSet
def interset(self,setB):
newSet = Set()
for element in setB:
if element in self:
newSet._theElements.append(element)
return newSet
def difference(self,setB):
newSet = Set()
for element in self:
if element not in setB:
newSet._theElements.append(element)
return newSet
def __iter__(self):
return iter(self._theElements)
插入$O(n)$,求并,交.差,等相$O(n^2)$,当然面后有通过排序来行进优化的.
面下就是Map了,不过其中额定应用了一个简略的存保key,value. 这个类似于stl中的 std::pair.
码代如下:
class Map:
def __init__(self):
self._entryList = list()
def __len__(self):
return len(self._entryList)
def __contains__(self,key):
ndx = self._findPosition(key)
return ndx is not None
def add(self,key,value):
ndx = self._findPosition(key)
if ndx is not None:
self._entryList.value = value
return False
else:
entry = _MapEntry(key,value)
self._entryList.append(entry)
return True
def valueOf(self,key):
ndx = self._findPosition(key)
assert ndx is not None,"Invalid map key"
return self._entryList.value
def remove(self,key):
ndx = self._findPosition(key)
ndx = self._findPosition(key)
assert ndx is not None,"Invalid map key"
self._entryList.pop(ndx)
def __iter__(self):
return _MapIterator(self._entryList)
def _findPosition(self,key):
for i in range(len(self)):
if self._entryList.key == key:
return i
return None
class _MapEntry:
def __init__(self,key,value):
self.key = key
self.value = value
class _MapIterator:
def __init__(self,mapRef):
self._curI = 0
self._mapRef = mapRef
def __iter__(self):
return self
def next(self):
if self._curI < len(self._mapRef):
entry = self._mapRef
self._curI += 1
return entry.key,entry.value
else:
raise StopIteration
嗯.都是很简略的.
睡觉拉..
文章结束给大家分享下程序员的一些笑话语录： 某程序员对书法十分感兴趣，退休后决定在这方面有所建树。花重金购买了上等的文房四宝。一日突生雅兴，一番磨墨拟纸，并点上了上好的檀香，颇有王羲之风 范，又具颜真卿气势，定神片刻，泼墨挥毫，郑重地写下一行字：hello world.
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