What is wrong with my code?

#1

Instead of using Subset generation using bit-masking, i used loops (not very efficient but just wanted to try) to get the different subsets but the something is wrong can someone help?

#2

where is the code ?
send the link

#3

#include<bits/stdc++.h>
using namespace std;
int main() {
int t;
cin>>t;
while(t–){

    long long n;
    cin>>n;
    long long ans = 0;
    long long arr[] = {2, 3, 5, 7, 11, 13, 17, 19};


    // Single
    for(int i = 0; i < 8 ; i++)
        ans += (n/arr[i]);
    
    
    // Double
    for(int i = 0 ; i < 8 ; i++)
        for(int j = i+1 ; j < 8 ; j++)
            ans -= (n/(arr[i]*arr[j]));
    
    
   // Triple
    for(int i = 0 ; i < 8 ; i++)
        for(int j = i+1 ; j < 8 ; j++)
            for(int k = j+1 ; k < 8 ; k++)
                ans += (n/(arr[i] * arr[j] * arr[k]));
    
    
    // four
    for(int i = 0 ; i < 8 ; i++)
        for(int j = i+1 ; j < 8 ; j++)
            for(int k = j+1 ; k < 8 ; k++)
                for(int l = k+1; l < 8 ; l++)
                    ans -= (n/(arr[i] * arr[j] * arr[k] * arr[l]));

    
    
    //five
    for(int i = 0 ; i < 8 ; i++)
        for(int j = i+1 ; j < 8 ; j++)
            for(int k = j+1 ; k < 8 ; k++)
                for(int l = k+1; l < 8 ; l++)
                    for(int m = l+1; m < 8; m++)
                        ans += (n/(arr[i] * arr[j] * arr[k] * arr[l] * arr[m]));
    
    
    
    //six
    for(int i = 0 ; i < 8 ; i++)
        for(int j = i+1 ; j < 8 ; j++)
            for(int k = j+1 ; k < 8 ; k++)
                for(int l = k+1; l < 8 ; l++)
                    for(int m = l+1; m < 8; m++)
                        for(int n = m+1; n < 8; n++)
                            ans -= (n/(arr[i] * arr[j] * arr[k] * arr[l] * arr[m] * arr[n]));
    
    
    //seven
    for(int i = 0 ; i < 8 ; i++)
        for(int j = i+1 ; j < 8 ; j++)
            for(int k = j+1 ; k < 8 ; k++)
                for(int l = k+1; l < 8 ; l++)
                    for(int m = l+1; m < 8; m++)
                        for(int n = m+1; n < 8; n++)
                            for(int o = n+1; o < 8; o++)
                            ans += (n/(arr[i] * arr[j] * arr[k] * arr[l] * arr[m] * arr[n] * arr[o]));
                        
    
    
    //all
    ans -= (n/(arr[0] * arr[1] * arr[2] * arr[3] * arr[4] * arr[5] * arr[6] * arr[7]));

    cout<<ans<<endl;
    


}
return 0;

}

#4

why are you dividing n with a[i]???
Any logic?

#5

Because thats how we calculate the number of numbers divisible by the prime number. a[i] stores one of the prime numbers lesser than 20.
Nevermind i solved it using subset method but this method should work as well. Dont really know why it didnt.

#6

if you are so confident on this method,
then dont leave it and try to find the bugs.
if its wrong its wrong.