Print all distinct circular strings of length M in lexicographical order

Given a string and an integer M, print all distinct circular strings of length M in lexicographical order. 

Examples: 

Input: str = “baaaa”, M = 3 
Output: aaa aab aba baa 
All possible circular substrings of length 3 are “baa” “aaa” “aaa” “aab” “aba” 
Out of the 6, 4 are distinct, and the lexicographical order is aaa aab aba baa 

Input: str = “saurav”, M = 4 
Output: aura avsa ravs saur urav vsau 
All possible circular substrings of length 4 are saur aura urav ravs avsa vsau. 
All the substrings are distinct, the lexicographical order is aura avsa ravs saur urav vsau.

Approach: The substr function is used to solve the problem. Append the string to itself at first. Iterate over the length of the string to generate all possible substrings of length M. Set is used in C++ to store all the distinct substrings of length 4, set by default stores all its elements in lexicographical order. Once all the strings are generated, print the elements in the set from the beginning. 

Below is the implementation of the above approach:

C++

// C++ program to print all
// distinct circular strings
// of length M in lexicographical order
#include <bits/stdc++.h>
using namespace std;

// Function to print all the distinct substrings
// in lexicographical order
void printStrings(string s, int l, int m)
{
    // stores all the distinct substrings
    set<string> c;

    // Append the string to self
    s = s + s;

    // Iterate over the length to generate
    // all substrings of length m
    for (int i = 0; i < l; i++) {

        // insert the substring of length m
        // in the set
        c.insert(s.substr(i, m));
    }

    // prints all the distinct circular
    // substrings  of length m
    while (!c.empty()) {

        // Prints the substring
        cout << *c.begin() << " ";

        // erases the beginning element after
        // printing
        c.erase(c.begin());
    }
}

// Driver code
int main()
{
    string str = "saurav";
    int N = str.length();
    int M = 4;

    printStrings(str, N, M);

    return 0;
}

Java

// Java program to print all
// distinct circular strings
// of length M in lexicographical order
import java.util.*;

class GFG
{

// Function to print all the distinct substrings
// in lexicographical order
static void printStrings(String s, int l, int m)
{
    // stores all the distinct substrings
    Set<String> c = new LinkedHashSet<>();

    // Append the string to self
    s = s + s;

    // Iterate over the length to generate
    // all substrings of length m
    for (int i = 0; i < l; i++)
    {

        // insert the substring of length m
        // in the set
            c.add(s.substring(i, i+m));
    }

    // prints all the distinct circular
    // substrings of length m
    Iterator itr = c.iterator();
    while (itr.hasNext())
    {

        // Prints the substring
        String a =(String) itr.next();
        System.out.print(a+" ");

    }
    c.clear();
}

// Driver code
public static void main(String[] args)
{
    String str = "saurav";
    int N = str.length();
    int M = 4;

    printStrings(str, N, M);
}
}

// This code contributed by Rajput-Ji

Python3

# Python program to print all
# distinct circular strings
# of length M in lexicographical order

# Function to print all the distinct substrings
# in lexicographical order
def printStrings(s, l, m):

    # stores all the distinct substrings
    c = set()

    # Append the string to self
    s = s+s

    # Iterate over the length to generate
    # all substrings of length m
    for i in range(l):

        # insert the substring of length m
        # in the set
        c.add(s[i:i+m])

    # prints all the distinct circular
    # substrings of length m
    for i in c:

        # Prints the substring
        print(i, end=" ")


# Driver code
if __name__ == "__main__":

    string = "saurav"
    N = len(string)
    M = 4

    printStrings(string, N, M)

# This code is contributed by
# sanjeev2552

C#

// C# program to print all
// distinct circular strings
// of length M in lexicographical order
using System;
using System.Collections.Generic;

class GFG
{
    // Function to print all the distinct substrings
    // in lexicographical order
    static void printStrings(String s, int l, int m)
    {
        // stores all the distinct substrings
        HashSet<string> c = new HashSet<string>();

        // Append the string to self
        s = s + s;

        // Iterate over the length to generate
        // all substrings of length m
        for (int i = 0; i < l; i++)
        {
            // insert the substring of length m
            // in the set
            c.Add(s.Substring(i, m));
        }

        // prints all the distinct circular
        // substrings of length m
        foreach (string i in c)
        {
            string a = (string)i;
            Console.Write(a + " ");
        }
        c.Clear();
    }

    // Driver code
    public static void Main(String[] args)
    {
        String str = "saurav";
        int N = str.Length;
        int M = 4;

        printStrings(str, N, M);
    }
}

// This code contributed by
// sanjeev2552

Javascript

<script>

// Javascript program to print all
// distinct circular strings
// of length M in lexicographical order

// Function to print all the distinct substrings
// in lexicographical order
function printStrings(s, l, m)
{

    // Stores all the distinct substrings
    var c = new Set();

    // Append the string to self
    s = s + s;

    // Iterate over the length to generate
    // all substrings of length m
    for(var i = 0; i < l; i++)
    {

        // Insert the substring of length m
        // in the set
        c.add(s.substring(i, i + m));
    }

    // Prints all the distinct circular
    // substrings  of length m
    while (c.size != 0)
    {

        var tmp = [...c].sort()[0];

        // Prints the substring
        document.write( tmp + " ");

        // Erases the beginning element after
        // printing
        c.delete(tmp);
    }
}

// Driver code
var str = "saurav";
var N = str.length;
var M = 4;

printStrings(str, N, M);

// This code is contributed by itsok

</script>

Output

aura avsa ravs saur urav vsau 

Time Complexity: O(N*M), where N is the length of the string.
Auxiliary Space: O(N*M)