Lex Fridman: evaluation

Transcript context

…Like, “Maybe I’m not a programmer. Maybe I’m not worthy enough to enter into this circle of people who can figure out what the heck recursion means.” And Deitel and Deitel’s, I still remember this, their exact phrase was, “Every young budding developer solves this recursion program,” and it was the Tower of Hanoi. And guess what? I don’t know if I can solve the Tower of Hanoi to this day. It’s a very hard recursive problem. And I just sat there and thought, ” Oh my gosh. I’m not going to make it.” And I sat there in the lab for eight hours, 10 hours doing these things, so worried. It’s the week of recursion, we have to do a lab assignment. “I’m not going to be able to do it.” And I just remember being genuinely worried about that. And then… Because always my big problem was like, “Okay, do factorial.” Why not just use a for loop? “Okay, what about Fibonacci sequence?” Why not use a for loop? I don’t understand. What’s the purpose of recursion? I don’t understand it yet. It’s so powerful. Why? It looks like a really complicated for loop. And so I just could not understand it. And then lab came that day and it was, “I’m going to give you a 2D array you have to read from a file. This is what a starting position looks like. This is what an ending position looks like. This is what a wall looks like. I want you to find me a path through the maze.” So I just sat there like, “Okay, well I guess I can just go up and I can create a visited grid, so I know not to visit these places anymore.” And then all of a sudden it just started clicking. Like, “Well, wait a second. I don’t know the maze, but if I just go up, right, down, and left, and hop back every time I’ve been to that square, don’t visit it, it will just go forever.” And I realized in that moment, I’m like, “I actually understand. I’ve understood recursion this whole time, I just never had a problem in which it actually made sense to use. And that was my big downfall, is that I was measuring my understanding with the problems that I had available, which were just list traversal, which is not a good use of recursion. And so I just remember that freeing… Oh, man. Recursion. It was a great moment in my life. I mean it does require, to be fair, a leap of faith, because people will tell you, those conformist, dogmatic, Java instructors will tell you, that this is important, to understand recursion. But it takes a leap of faith that this is a different way of looking at the world, and it’s a powerful way of looking at the world. Actually, I think I remember my first now. All right.…

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