ordering_subsets.cpp

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

bool compare(string a ,string b){
    if(a.length()==b.length()){
        return a<b; //lexicographic order
    }
    return a.length()<b.length();
}

void finding_subsets(char *input,char *output, int i , int j, vector<string> &list){
     //base case
    if(input[i] =='\0'){
        output[j] = '\0';
        string temp(output);
        list.push_back(temp);
        return;

    }
    //recursive case
     output[j]= input[i];
     finding_subsets(input,output,i+1,j+1,list);
     finding_subsets(input,output,i+1,j,list);

}
int main(){
    char input[100];
    char output[100];
    vector<string> list;
    cin>>input;
    finding_subsets(input,output,0,0,list);
    sort(list.begin(),list.end(),compare);
    //print the output
    for(auto s:list){
        cout<<s<<"," ;
    }
    return 0;

}