added the code for adding the numeric value of two likedlist representation of digits
added the initial part of the code for finding the 3 digits from individual linkedlists so that it equals certain sum
modified the name of the existing file and also removed few sysout statements in between the mergelistAlternatively code
added the code for the implementation of mergesort in linkedlists
added the code for finding the intersection and the union of a list. in this code both intersection and union cannot be performed one after other because the code uses the same node constructed for the orginal linked lists
added the initial few bits of the code for the construction of mem efficient xor linkedlist code