NVIDIA interview questions

Submitted CV in career fair and did on the spot interview

Had an initial phone interview for a senior software engineer position. But my level is intermediate. The interviewer is clear and asked me appropriate questions relative to that position. 1. How will you create Singleton class, lazy initialization, thread safety etc. 2. How will you find odd element in an array full of duplicate elements. 3. Tell an SQL statement that can find all employees with the same manager ID given the employee ID.