#=======================================================================
# Author: Isai Damier
# Title: Singly Linked List
# Project: geekviewpoint
# Package: datastructure
#
# Description: A LinkedList is a data structure that allows access
# to a collection of data using pointers/references. While an
# array can also be defined as above, LinkedLists and arrays differ
# in how they are stored in memory and in the operations they
# allow. Unlike an array that must be stored in a block of memory,
# the nodes of a LinkedList can be stored anywhere because each
# node has a reference to the node that succeeds it. Because the
# nodes are stored so loosely, inserting nodes into a LinkedList
# is easy; whereas in an array, all the succeeding elements must
# be shifted. Of course, insertion also means changing the size of
# the array, which means creating the entire array anew.
#
# Perhaps the greatest beauty of LinkedList is that it allows
# accessing an entire sequence of nodes using only one variable:
# a reference to the first node in the sequence.
#
# Countless operations can be performed on LinkedLists. Following
# are a few, ranging from the common to the very interesting.
#=======================================================================
#=====================================================================
# Time Complexity of Solution:
# O(n).
#
# Description: Add all the nodes of the given list to this linked list.
#=====================================================================
import collections
class SinglyLinkedList( object ):
def __init__( self ):
self.head , self.tail = None, None
def addAllToTail( self, subHead ):
if None == subHead:
return
if self.isEmpty():
self.head = subHead
else:
self.tail.next = subHead
while None != subHead.next:
subHead = subHead.next
self.tail = subHead
class Node( object ):
def __init__( self, data, next = None ):
self.data = data
self.next = next
class Node( object ):
def __init__( self, data, next = None ):
self.data = data
self.next = next
import unittest
from algorithms.SinglyLinkedList import SinglyLinkedList
import random
class Test( unittest.TestCase ):
#=====================================================================
# Test of addAllToTail method, of class SinglyLinkedList.
#=====================================================================
def testAddAllToTail( self ):
in_1 = [29, 14, 35, 2, 1, 12]
in_2 = [99, 78, 8, 3, 23]
list_1 = SinglyLinkedList()
list_2 = SinglyLinkedList()
for i in range( len( in_1 ) ):
list_1.addToTail( in_1[i] )
self.assertEquals( len( in_1 ), list_1.size() )
for i in range( len( in_2 ) ):
list_2.addToTail( in_2[i] )
self.assertEquals( len( in_2 ), list_2.size() )
list_2.addAllToTail( list_1.head )
self.assertEquals( len( in_1 ) + len( in_2 ), list_2.size() )