1) Initialize two index variables left and right: 
left = 0, right = size -1 
2) Keep incrementing left index until we see an even number.
3) Keep decrementing right index until we see an odd number.
4) If left < right then swap arr[left] and arr[right]

Reverse the first sub-list of size k. While reversing keep track of the next node and previous node. Let the pointer to the next node be next and pointer to the previous node be prev. 
head->next = reverse(next, k) ( Recursively call for rest of the list and link the two sub-lists )
Return prev ( prev becomes the new head of the list

Tip 1 : Have knowledge about the company you are applying to
Tip 2 : Be confident