Leetcode has taught me that I'm a bad engineer

  There is no memorization involved, just like you don't memorize every math problem on earth to map directly to a correct answer you instead derive the answer using the skills you have in math from experience solving problems before. Polya has a book for this, called 'How to Solve It' he just happens to have used math to teach problem solving but it's the exact same concept.

  You have at your disposal problem solving strategies such as: complete search, dynamic programming, greedy and divide and conquer. You don't need to memorize any code to write a greedy search, you could ad-hoc hack that together just know what a greedy strategy is. You don't memorize all search algorithms throughout history ever invented.

  There is no grind. People who haven't done it assume you sit there for hours daily writing brute force algorithms, no. Instead it's exactly like doing a crossword puzzle over a coffee and something you can do at your leisure where in a month or so you're now at leetcode medium/hard no problem.