Generating all subsequence using Bit Masking in C++

 Generating all subsequence using Bit Masking in C++

 Here is the code 

#include<bits/stdc++.h>

using namespace std;

vector<string>res;

void helper(vector<char>s,int i){

    int j=0;

    string ans="";

    while(i>0){

        int last_bit=(i & 1);

        if(last_bit)ans+=s[j];

        j++;

        i=(i>>1);

    }

    res.push_back(ans);

}

void generateAllSubsequence(vector<char>s){

    int n=s.size();

    for(int i=0; i<(1<<n); i++){

        helper(s,i);

    }

}

int main(){

    vector<char>v={'r','a','u','n','i','t'};

    generateAllSubsequence(v);

    for(int i=0; i<res.size(); i++)cout<<i<<" "<<res[i]<<endl;

    return 0;

}

Here is the Output

0 

1 r

2 a

3 ra

4 u

5 ru

6 au

7 rau

8 n

9 rn

10 an

11 ran

12 un

13 run

14 aun

15 raun

16 i

17 ri

18 ai

19 rai

20 ui

21 rui

22 aui

23 raui

24 ni

25 rni

26 ani

27 rani

28 uni

29 runi

30 auni

31 rauni

32 t

33 rt

34 at

35 rat

36 ut

37 rut

38 aut

39 raut

40 nt

41 rnt

42 ant

43 rant

44 unt

45 runt

46 aunt

47 raunt

48 it

49 rit

50 ait

51 rait

52 uit

53 ruit

54 auit

55 rauit

56 nit

57 rnit

58 anit

59 ranit

60 unit

61 runit

62 aunit

63 raunit