Print all possible strings that can be made by placing spaces using Power Set

Given a string you need to print all possible strings that can be made by placing spaces (zero or one) in between them 

Examples :

Input :  str[] = "ABC"
Output : ABC
         AB C
         A BC
         A B C

Input : str[] = "ABCD"
Output : ABCD
         A BCD
         AB CD
         A B CD
         ABC D
         A BC D
         AB C D
         A B C D

If we take a  closer look, we can notice that this problem boils down to Power Set problem. We basically need to generate all subsets where every element is a different space.  

Implementation:

C++

// C++ program to print all strings that can be
// made by placing spaces
#include <bits/stdc++.h>
using namespace std;

void printSubsequences(string str)
{
    int n = str.length();
    unsigned int opsize = pow(2, n - 1);

    for (int counter = 0; counter < opsize; counter++) {
        for (int j = 0; j < n; j++) {

            cout << str[j];
            if (counter & (1 << j))
                cout << " ";
        }
        cout << endl;
    }
}

// Driver code
int main()
{
    string str = "ABC";
    printSubsequences(str);
    return 0;
}

Java

// Java program to print all strings that can be
// made by placing spaces
import java.util.*;
class GFG
{
static void printSubsequences(String s)
{
    char[] str= s.toCharArray();
    int n = str.length;
    int opsize = (int)(Math.pow(2, n - 1));

    for (int counter = 0; counter < opsize; counter++) {
        for (int j = 0; j < n; j++) {

            System.out.print(str[j]);
            if ((counter & (1 << j)) > 0)
                System.out.print(" ");
        }
        System.out.println();
    }
}

// Driver code
public static void main(String[] args)
{
    String str = "AB";
    printSubsequences(str);
}
}

/* This code is contributed by Mr. Somesh Awasthi */

Python3

# Python 3 program to print all strings
# that can be made by placing spaces
from math import pow

def printSubsequences(str):
    n = len(str)
    opsize = int(pow(2, n - 1))

    for counter in range(opsize):
        for j in range(n):
            print(str[j], end = "")
            if (counter & (1 << j)):
                print(" ", end = "")

        print("\n", end = "")

# Driver code
if __name__ == '__main__':
    str = "ABC"
    printSubsequences(str)

# This code is contributed by
# Sanjit_Prasad

C#

// C# program to print all strings
// that can be made by placing spaces
using System;

class GFG {

    // Function to print all subsequences
    static void printSubsequences(String s)
    {
        char[] str= s.ToCharArray();
        int n = str.Length;
        int opsize = (int)(Math.Pow(2, n - 1));

        for (int counter = 0; counter < opsize;
                                     counter++)
        {
            for (int j = 0; j < n; j++)
            {
                Console.Write(str[j]);

                if ((counter & (1 << j)) > 0)
                    Console.Write(" ");
            }
            Console.WriteLine();
        }
    }

    // Driver code
    public static void Main()
    {
        String str = "ABC";
        printSubsequences(str);
    }
}

// This code is contributed by shiv_bhakt.

PHP

<?php
// PHP program to print
// all strings that can be
// made by placing spaces

function printSubsequences($str)
{
    $n = strlen($str);
    $opsize = pow(2, $n - 1);

    for ($counter = 0;
         $counter < $opsize;
         $counter++)
    {
        for ($j = 0; $j < $n; $j++)
        {
            echo $str[$j];
            if ($counter & (1 << $j))
                echo " ";
        }
        echo "\n";
    }
}

// Driver code
$str = "ABC";
printSubsequences($str);

// This code is contributed by ajit
?>

Javascript

<script>

// Javascript program to print all strings
// that can be made by placing spaces

// Function to print all subsequences
function printSubsequences(s)
{
    let str= s.split('');
    let n = str.length;
    let opsize = Math.pow(2, n - 1);

    for(let counter = 0; counter < opsize; counter++)
    {
        for(let j = 0; j < n; j++)
        {
            document.write(str[j]);

            if ((counter & (1 << j)) > 0)
                document.write(" ");
        }
        document.write("</br>");
    }
}

// Driver code
let str = "ABC";
printSubsequences(str);

// This code is contributed by rameshtravel07
</script>

Output

ABC
A BC
AB C
A B C

Time complexity : O(n*2^n-1) 
Auxiliary Space : O(1)

Asked in: Amazon
/p>

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