Insert a node at a specific position in a linked list

More practice on May 9, 2016
Linked List on HackerRank:
problem statements:
https://www.hackerrank.com/domains/data-structures/linked-lists/difficulty/all/page/1


Insert a node at a specific position:
https://gist.github.com/jianminchen/5b357be38d6bad427e885c7b7343c19b