Some cases don't work in this cpp code

Question

#include <iostream>
using namespace std;

int q(int n){
if((n==1)||(n==2)){
return 1;
}else{
return (q(n-(q(n-1)))+q(n-(q(n-2))));
}
}

int main() {
int n;
cin>>n;
cout<<q(n);
return 0;
}

Answer 1

Going down the memoization rabbit hole with Python, it is actually able to handle larger values of n than the C++ ones, primarilly because you cannot set the stack size for the C++ compiler in Sololearn...

https://sololearn.com/compiler-playground/cBs1xhrEC4AA/?ref=app

Answer 2

As far as I know, the execution time limit in playground is 10 seconds.
If your program need a time longer than that, it will time out and display "no output".

Answer 3

use memoization to speed it up. There will still be a limit, but it will be higher. Your function calls easily go beyond millions for n>=11 without memoization. That is the penalty of recursive functions. Memoization reduces the function call count.

https://sololearn.com/compiler-playground/cm3ECuHl1Fp8/?ref=app
https://sololearn.com/compiler-playground/cin4yr31dCUY/?ref=app
https://sololearn.com/compiler-playground/c0aDmyOTP87q/?ref=app