How I fix my code that gives segmentation fault?

My code gives Segmentation fault when i run it.I do not understand its reason.Why?

input 4 6

int solve(int s, int f){
    if(s==f){
            return 0;
    }
    if(s>f){
            return s-f;
    }
    if(s>=0){
    return min(solve(s-1,f)+1,solve(s*2,f)+1);
    }
    else{
    return 0;
    }
}
int main(){
    int n,m;
    cin>>n>>m;
    cout<<solve(n,m)<<'\n';
    return 0;
}

>Solution :

You have infinite recursion. For your example input 4 6, you call:

// from main: 
solve(4, 6)
// inside that call we have
min(solve(3, 6)+1, solve(8, 6)+1);
//  ^ from this one
min(solve(2, 6)+1, solve(6, 6)+1);
//  ^ from this one
min(solve(1, 6)+1, solve(4, 6)+1);
//                 ^ back to beginning

I don’t know what this program is supposed to do, but you need to rethink your algorithm.