Nson - 9 months ago 43

C++ Question

I am currently trying to make a program which involves ascending sequences. N is for the size of the sequence and K is the maximum number, for example

Input:

`2,3`

Output:

`6 (1,1 - 1,2 - 1,3 - 2,2 - 2,3 - 3,3)`

My current code doesn't output 6 but 3. I know this is probably not the way to find the amount of sequences. From what I see, something is wrong in the recursion. Can you please help me find the problem and fix it?

`#include<iostream>`

using namespace std;

long long n,k,cnt=0;

long long seq(long long n, long long k, long long first){

if(n==first){

return cnt;

}

for(long long i=first;i<=k;i++){

cnt = cnt + 1;

}

return seq(n,k,first+1);

}

int main()

{

long long n,k;

cin>>n>>k;

cout<<seq(n,k,1);

return 0;

}

Answer Source

This function should do it for a given n and k

```
long long seq(long long n, long long k,long long first,long long depth){
if(depth > n){
cnt = cnt + 1; // A leaf node is hit in the recursion tree
return cnt;
}
else {
for(long long i= first;i<=k;i++){
seq(n,k,i,depth+1); // Continue recursion
}
}
return cnt;
}
int main()
{
long long n,k;
cin>>n>>k;
cout<<seq(n,k,1,1);
return 0;
}
```

Running code here : http://cpp.sh/4xr7a