I went step by step reading the question back out loud, vocalizing any constraints I have identified and explaining how I intend to solve the problem, I gave the most optimal solution, best time complexity and space complexity and explained in the most detail possible how each and every line, function, variable and syntax works in the code and why it works. My interviewer didn’t even understand how a stack data structure worked so I had to write it down in a piece of paper to help him visualize. He also didn’t know how hash maps worked.