Question

class Node(object):
def __init__(self, data, next=None):
self.data = data
self.next = next

class List(object):   
def __init__(self):
self.head = None
self.tail = None

Implement the following functions for Linked List in Python and use the constructors above :

Copy(lList) Builds and returns a copy of list

ItemAt(List,i) Returns the data item at position i in list Pop(List,i=0)

Remove item at position i in list. If i is not specified, it removes the first item in list

Count(List,x) Returns the number of times x appears in list.

Index(List,x) Returns the index of the first item whose value is equal to x list

Clear(List) Removes all items from list.

Sublist(list,start=0,end=GetLength(List)) Builds and returns a sublist of list, from element start to element end (not inclusive).

all functions must use pass by reference

Answer 1

CODE :

class Node(object):
def __init__(self,data,next=None):
self.data = data
self.next = next
  
def __repr__(self):
return str(self.data);
  
class List(object):
def __init__(self):
self.head = None
self.tail = None
  
def add(self,x):
if self.head is None:
self.head = Node(x)
self.tail = self.head
return
temp = self.head
while temp.next is not None:
temp = temp.next
temp.next = Node(x)
self.tail = temp.next
  
def print(self):
temp = self.head
while temp is not None:
print(temp.data,'->',end='')
temp = temp.next
print()
  
def Copy(self):
iList = self
if iList.head is None:
return None
temp = iList.head
newhead = Node(iList.head.data)
temp2 = newhead
prevv = newhead
while temp.next is not None:
temp = temp.next
temp2.next = Node(temp.data)
prevv = temp
temp2 = temp2.next
ans = List()
ans.head = newhead
ans.tail = prevv
return ans
  
def ItemAt(self,i):
iList = self
if i==0:
return iList.head
temp = iList.head
for i in range(i):
temp = temp.next
return temp
def Pop(self,i=0):
iList = self
if i==0:
iList.head = iList.head.next
return
prev = iList.head
temp = iList.head
for x in range(i):
prev = temp
temp = temp.next
cnext = temp.next
prev.next = cnext
return temp
  
def Count(self,x):
iList = self
temp = iList.head
ans = 0
while temp is not None:
if temp.data == x:
ans+=1
temp = temp.next
return ans
  
def Index(self,x):
iList = self
ind = 0
temp = iList.head
while temp is not None:
if temp.data==x:
return ind
ind+=1
temp = temp.next
  
def Clear(self):
iList = self
iList.head = None
iList.tail = None
  
def GetLength(self):
iList = self
ans = 0
temp = iList.head
while temp is not None:
ans += 1
temp = temp.next
return ans
  
def SubList(self,start=0,end=0):
iList = self
temp = iList.head
for x in range(start):
temp = temp.next
print(temp)
ans = Node(temp.data)
temp2 = ans
prev = ans
for i in range(end-start):
temp = temp.next
temp2.next = Node(temp)
prev = temp2
temp2= temp2.next
#temp = temp.next
fans = List()
fans.head = ans
fans.tail = prev
return fans
  
l = List()
l.add(2)
l.add(3)
l.add(4)
l.add(5)
l.add(6)
print('List is ')
l.print()
print('Copied')
cpy = l.Copy()
cpy.print()
print('sublist 1-4')
l.SubList(1,4).print()

OUTPUT :

List is
2 ->3 ->4 ->5 ->6 ->
Copied
2 ->3 ->4 ->5 ->6 ->
sublist 1-4
3
3 ->4 ->5 ->6 ->