im trying to make a solution for this problem without using the modulo concept https://www.codechef.com/problems/CHRL4 but my output is always coming wrong. please help someone.

#include <bits/stdc++.h>

using namespace std;

int main()

{

int n, k, p, i, e, f, temp;

cin >> n >> k;

int a[100000];

for (i=0; i<n; i++)

cin >> a[i];

```
p=1;
for (i=0; i<=n; i++) {
while (1<=n-1 && n-1>=k) {
p *=a[i];
i++;
n--;
}
}
f=p*n*1;
cout << f;
return 0;
```

}