018.Factorials_Less_than_or_Equal_to_n.cpp

//Factorials Less than or Equal to n - gfg(easy) (acc : 48%)
//https://www.geeksforgeeks.org/problems/find-all-factorial-numbers-less-than-or-equal-to-n3548/0?problemType=functional&difficulty%255B%255D=-1&page=1&query=problemTypefunctionaldifficulty%255B%255D-1page1
/*
A number n is called a factorial number if it is the factorial of a positive integer. For example, the first few factorial numbers are 1, 2, 6, 24, 120,
Given a number n, the task is to return the list/vector of the factorial numbers smaller than or equal to n.
*/
//{ Driver Code Starts
#include <bits/stdc++.h>
using namespace std;


// } Driver Code Ends
// User function Template for C++
class Solution {
  public:
  long long cnt = 1;
    void fun(long long n, vector <long long>& ans, long long i) {
        if (i * cnt <= n) {
            i *= cnt;
            cnt++;
            ans.push_back(i);
            fun(n, ans, i);
        }
        else return;
    }
    vector<long long> factorialNumbers(long long n) {
        vector <long long> ans;
        fun(n, ans, 1);
        return ans;
    }
};

//{ Driver Code Starts.
int main() {
    int t;
    cin >> t;
    while (t--) {
        long long N;
        cin >> N;
        Solution ob;
        vector<long long> ans = ob.factorialNumbers(N);
        for (auto num : ans) {
            cout << num << " ";
        }
        cout << endl;
        cout << "~" << endl;
    }
    return 0;
}
// } Driver Code Ends