Northrop Grumman interview questions

I had an interview with the HR rep who then passed me along for another interview with the hiring manager. The interview with the hiring manager was pretty straight forward.

Went to an on-site interview and prepped based on other GD reviews, brushed up on my technical terms and made sure I knew my resume in and out. However, the interview was mainly leetcode/whiteboarding (80-90%). I was completely blindsided.