Software Engineer

The basic idea is to maintain a hash table for each element num in nums, using num as key and its index (0-based) as value. For each num, search for target - num in the hash table. If it is found and is not the same element as num, then we are done.

To solve this, I firstly gave a brute force approach after which the interviewer asked me to give an optimal solution, so I 
gave him the two pointer approach to solve this.
I took two nodes so that one can follow the other i.e. if one node is at index 0, other will be at index 1.
I maintained a count of total number of node to reach the nth node from end. 
Keep increasing the nodes one by one till count does not gets equal to (N-M+1), (N = number of nodes, M = nth node from last).
When count is equal to N-M+1, point the slow node's next to fast node's next and free the fast node.
With this approach the interviewer was satisfied.

Tip 1 : Be confident and speak carefully while being modest but not too much
Tip 2 : Be optimistic and eager to learn and reflect this in interview