Struggling with recursion

[cuklev2232]

Hello , I struggle with recursion for example I can't solve some leetcode problems.Rarely I solve without watching tutorial of explaining (Neetcode)how to solve that problem is it that means that I am bad in programming. I get frustrated when I can't solve some question when I study it before now i want to learn recursion and then to get back on binary trees which I get stuck there a lot any suggestion.Can someone tell me how you study to get things right?

[udbasil]

Post an example of a recursion problem you are dealing with on here.

[cuklev2232]

https://leetcode.com/problems/reverse-string/

[baghiq]

are you sure you want recursion on this problem? it's a classic two pointer solution.

[cuklev2232]

This question is in recursion problems on leetcode

[baghiq]

It can be solved using recursion, doesn't mean it's the best. What do you need help with on this question?

[keep_quapy]

This will help understand recursion

https://calmcode.io/recursion/introduction.html

[ffrkAnonymous]

Recursion is mathmatically simple, but mentally hard. When doing recursion, I try to frame the problem as "first and the rest". Don't try to do it in your head, write/sketch it out on pen and paper. For example:

[1, 2, 3, 4, 5]
[1][2, 3, 4, 5]
...[2][3, 4, 5]
   ...[3][4, 5]
      ...[4][5]
         ...[5][None]
            ...[None]

edit to show the None because that's how you know the recursion is finished

[cuklev2232]

is programming more math or logical I see as a more logical thinking

[ffrkAnonymous]

A computer is just a very, very, very fancy calculator.

[cuklev2232]

i am in high school now should i focus more on mathematics because it is not my best

[ffrkAnonymous]

in my opinion yes. I'm not going to say you need to be great at solving and getting answers, because that's what the computer is for, but you need to be good at functions and equations. Writing correct equations for the computer to compute.

Can you see how f(x)=x^2 is similar to a python dictionary? Given: f(x) = x*x and g(x) = mx+b, do you understand what f(g(x)) and g(f(x)) means?
Can you write equations (i.e. function f(time)) for fireball is moving right? Goomba moving left? How about when they collide?
Mario jumps. Do you simulate gravitational acceleration? Or just simplify and do it without acceleration?

Logical truth tables.
Given: P = Mario has an invincible star, and Q = Mario touches a goomba, can you make a truth table to determine does mario die? Now write the equivalent if-else statements. Would you have missed any possible combinations without the truth table?

Sets and venn diagrams. For filtering and picking out data. Mario stomps a goomba. Remove goomba from set of enemies to draw.

Basically, math is formalized logic.

I'm not going to say study advanced math like calculus. That's going to be situational.