National Instruments Applications Engineer interview questions

The interview was very smooth and the person was very calm and went on very nice and asked me and even guided me through out the interview. He calmed me throughout and was a nice person to talk too so all in all my interview though didnt went good but the person was very supportive even if i gave wrong answers

First there was a written test which consisted of questions from Scheduling (OS), Finite Automata , Compiler, etc. After that there was a coding round in which they asked 2 questions: 1.Find if palindrome can be formed from a given string.If so then print it.If there are more than one palindromes possible print the alphabetically first one. All this must be done in linear time (O(n)). 2.A problem involving Graph data structure.