citrix placement question

Today Citrix came to our campus,
The written round had 57 questions from
OS---20
Networking--1
Microprocessor---3
rest C and aptitude.

Then there was a coding round:

the questions were
1
a) Write a function which takes 3 integers x,p,n which flips 'n' bits of x from 'p'th position.(Count LSB=0).
b) Write a program to find the Kth smallest element in a BST.
2
Your are given a doubly linked list such that one link points to the immediate next node and other link points to some arbitary nodes in the doubly linked list.
Write a function to duplicate such doubly linked lists.

The interview had questions from OS and Networking.