Recursion2DArraySubsets.cpp

//Form subsets containg the elements of the 2D input array and return them. 
//Provided you mainatin the sequence of elemnts of the original input array
#include <bits/stdc++.h>
using namespace std;

int subset(int input[], int n, int output[][20]){
 if(n<=0) {
      output[0][0]=0;
      return 1;
  }

  int smallOutput = subset(input+1,n-1,output);
  
  for(int i=0;i<smallOutput;i++) {
      int col = output[i][0] +1;
     output[i+smallOutput][0] = col;
       output[i+smallOutput][1] = input[0];
      for(int j=2; j<col+1;j++) {
        output[i+smallOutput][j] = output[i][j-1];
      }

  }

  return 2*smallOutput;
}


int main() {
  int input[20],length, output[1000][20];
  cin >> length;
  for(int i=0; i < length; i++)
    cin >> input[i];
  
  int size = subset(input, length, output);

  for( int i = 0; i < size; i++) { 
	for( int j = 1; j <= output[i][0]; j++) { 
		cout << output[i][j] << " ";
    }
    cout << endl;
  }
}