All possible strings of any length that can be formed from a given string

Given a string of distinct characters, print all possible strings of any length that can be formed from given string characters.

Examples:

Input: abc
Output: a b c abc ab ac bc bac bca 
         cb ca ba cab cba acb

Input: abcd
Output: a b ab ba c ac ca bc cb abc acb bac
         bca cab cba d ad da bd db abd adb bad 
         bda dab dba cd dc acd adc cad cda dac 
         dca bcd bdc cbd cdb dbc dcb abcd abdc 
         acbd acdb adbc adcb bacd badc bcad bcda 
         bdac bdca cabd cadb cbad cbda cdab cdba 
         dabc dacb dbac dbca dcab dcba 

The generation of all strings include the following steps.
1) Generate all subsequences of given string.
2) For every subsequence ‘subs’, print all permutations of ‘subs’



Below is C++ implementation. It uses next_permutation function in C++.

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/*  C++ code to generate all possible strings
    that can be formed from given string */
#include<bits/stdc++.h>
using namespace std;
  
void printAll(string str)
{
    /* Number of subsequences is (2**n -1)*/
    int n = str.length();
    unsigned int opsize = pow(2, n);
  
    /* Generate all subsequences of a given string.
       using counter 000..1 to 111..1*/
    for (int counter = 1; counter < opsize; counter++)
    {
        string subs = "";
        for (int j = 0; j < n; j++)
        {
            /* Check if jth bit in the counter is set
                If set then print jth element from arr[] */
            if (counter & (1<<j))
                subs.push_back(str[j]);
        }
  
        /* Print all permutations of current subsequence */
        do
        {
            cout << subs << " ";
        }
        while (next_permutation(subs.begin(), subs.end()));
    }
}
  
// Driver program
int main()
{
    string str = "abc";
    printSubsequences(str);
    return 0;
}

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Output:

a b ab ba c ac ca bc cb abc acb bac bca cab cba

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Improved By : Akanksha_Rai



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