Composite Series

// { Driver Code Starts
//Initial Template for C++

#include<bits/stdc++.h>
using namespace std;

 // } Driver Code Ends


//User function Template for C++

class Solution{
public:
    vector<int> compositeNumbers(int N){
        // code here
         int arr[N+1]={0};
        for(int i=2;i<=sqrt(N);i++){
            int k=i;
            k+=i;
            while(k<=N){
                arr[k]=1;
                k+=i;
            }
        }
        vector<int> vec;
        for(int i=2;i<=N;i++){
            if(arr[i]!=0){vec.push_back(i);}
        }
        return vec;
    }
};

// { Driver Code Starts.

int main(){
    int t;
    cin>>t;
    while(t--){
        int N;
        cin>>N;
        
        Solution ob;
        vector<int> ans = ob.compositeNumbers(N);
        for(int u: ans)
            cout<<u<<" ";
        cout<<"\n";
    }
    return 0;
}  // } Driver Code Ends