Find substrings that contain all vowels

We have been given a string in lowercase alphabets. We need to print substrings that contain all the vowels at least one time and there are no consonants (non-vowel characters) present in the substrings.

Examples:

Input : str = aeoibddaeoiud
Output : aeoiu

Input : str = aeoibsddaeiouudb
Output : aeiou, aeiouu

Reference:- Samsung Interview Questions.

We use a hashing based technique and start traversing the string from the start. For every character, we consider all substrings starting from it. If we encounter a consonant, we move to the next starting character. Else, we insert the current character in a hash. If all vowels are included, we print the current substring. 

Implementation:

C++

// CPP program to find all substring that
// contain all vowels
#include <bits/stdc++.h>

using namespace std;

// Returns true if x is vowel.
bool isVowel(char x)
{
    // Function to check whether a character is
    // vowel or not
    return (x == 'a' || x == 'e' || x == 'i' ||
                        x == 'o' || x == 'u');
}

void FindSubstring(string str)
{
    set<char> hash; // To store vowels

    // Outer loop picks starting character and
    // inner loop picks ending character.
    int n = str.length();
    for (int i = 0; i < n; i++) {
       for (int j = i; j < n; j++) {

            // If current character is not vowel,
            // then no more result substrings
            // possible starting from str[i].
            if (isVowel(str[j]) == false)
              break;

            // If vowel, then we insert it in hash
            hash.insert(str[j]);

            // If all vowels are present in current
            // substring
            if (hash.size() == 5)
                cout << str.substr(i, j-i+1) << " ";
        }

        hash.clear();
    }
}

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

Java

// Java program to find all substring that
// contain all vowels
import java.util.HashSet;

public class GFG {

    // Returns true if x is vowel.
    static boolean isVowel(char x) {
        // Function to check whether a character is
        // vowel or not
        return (x == 'a' || x == 'e' || x == 'i'
                || x == 'o' || x == 'u');
    }

    static void findSubstring(String str) {
        HashSet<Character> hash = new HashSet<Character>();
            // To store vowels

        // Outer loop picks starting character and
        // inner loop picks ending character.
        int n = str.length();
        for (int i = 0; i < n; i++) {
            for (int j = i; j < n; j++) {

                // If current character is not vowel,
                // then no more result substrings
                // possible starting from str[i].
                if (isVowel(str.charAt(j)) == false)
                    break;

                // If vowel, then we insert it in hash
                hash.add(str.charAt(j));

                // If all vowels are present in current
                // substring
                if (hash.size() == 5)
                    System.out.print(str.substring(i, j + 1) + " ");
            }
            hash.clear();
        }
    }

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

Python3

# Python3 program to find all substring that
# contain all vowels

# Returns true if x is vowel.
def isVowel(x):

    # Function to check whether a character is
    # vowel or not
    if (x == 'a' or x == 'e' or x == 'i' or
        x == 'o' or x == 'u'):
        return True
    return False

def FindSubstring(str1):

    # To store vowels

    # Outer loop picks starting character and
    # inner loop picks ending character.
    n = len(str1)
    for i in range(n):
        hash = dict()
        for j in range(i, n):

            # If current character is not vowel,
            # then no more result substrings
            # possible starting from str1[i].
            if (isVowel(str1[j]) == False):
                break

            # If vowel, then we insert it in hash
            hash[str1[j]] = 1

            # If all vowels are present in current
            # substring
            if (len(hash) == 5):
                print(str1[i:j + 1], end = " ")

# Driver code
str1 = "aeoibsddaeiouudb"
FindSubstring(str1)

# This code is contributed by Mohit Kumar

C#

// C# program to find all substring that
// contain all vowels
using System;
using System.Collections.Generic;

public class GFG
{

// Returns true if x is vowel.
public static bool isVowel(char x)
{
    // Function to check whether a
    // character is vowel or not
    return (x == 'a' || x == 'e' ||
            x == 'i' || x == 'o' || x == 'u');
}

public static void findSubstring(string str)
{
    HashSet<char> hash = new HashSet<char>();

    // To store vowels
    // Outer loop picks starting character and
    // inner loop picks ending character.
    int n = str.Length;
    for (int i = 0; i < n; i++)
    {
        for (int j = i; j < n; j++)
        {

            // If current character is not vowel,
            // then no more result substrings
            // possible starting from str[i].
            if (isVowel(str[j]) == false)
            {
                break;
            }

            // If vowel, then we insert it in hash
            hash.Add(str[j]);

            // If all vowels are present in current
            // substring
            if (hash.Count == 5)
            {
                Console.Write(str.Substring(i,
                             (j + 1) - i) + " ");
            }
        }
        hash.Clear();
    }
}

// Driver code
public static void Main(string[] args)
{
    string str = "aeoibsddaeiouudb";
    findSubstring(str);
}
}

// This code is contributed by Shrikant13

Javascript

<script>
// Javascript program to find all substring that
// contain all vowels

    // Returns true if x is vowel.
    function isVowel(x)
    {
        // Function to check whether a character is
        // vowel or not
        return (x == 'a' || x == 'e' || x == 'i'
                || x == 'o' || x == 'u');
    }

    function findSubstring(str)
    {
        let hash = new Set();
            // To store vowels

        // Outer loop picks starting character and
        // inner loop picks ending character.
        let n = str.length;
        for (let i = 0; i < n; i++) {
            for (let j = i; j < n; j++) {

                // If current character is not vowel,
                // then no more result substrings
                // possible starting from str[i].
                if (isVowel(str[j]) == false)
                    break;

                // If vowel, then we insert it in hash
                hash.add(str[j]);

                // If all vowels are present in current
                // substring
                if (hash.size == 5)
                    document.write(str.substring(i, j + 1) + " ");
            }
            hash.clear();
        }
    }

    // Driver code
    let str = "aeoibsddaeiouudb";
    findSubstring(str);


// This code is contributed by patel2127
</script>

Output

aeiou aeiouu 

Time Complexity : O(n²)
Auxiliary Space: O(1)

Sliding Window Approach -:

Algorithm -:

1. Create a HashSet hash to store vowels.
2. Initialize a variable start to 0.
3. Traverse the string from left to right using a for loop:
    a. If the current character is a vowel, add it to the hash.
    b. If the size of the hash is 5 (all vowels are present in the current substring), print the substring from start to i+1.
    c. If the current character is not a vowel, update the start to i+1 and clear the hash.

Implementation:

C++

// C++ program to find all substring that
// contain all vowels
#include<bits/stdc++.h>

using namespace std;

// Returns true if x is vowel.
bool isVowel(char x)
{
    // Function to check whether a character is
    // vowel or not
    return (x == 'a' || x == 'e' || x == 'i' ||
                        x == 'o' || x == 'u');
}

// Function to FindSubstrings of string
void FindSubstring(string str)
{
    set<char> hash;  // To store vowels

    int start = 0;
    for (int i=0; i<str.length(); i++)
    {
        // If current character is vowel then
        // insert into hash ,
        if (isVowel(str[i]) == true)
        {
            hash.insert(str[i]);

            // If all vowels are present in current
            // substring
            if (hash.size()==5)
                cout << str.substr(start, i-start+1)
                     << " ";
        }
        else
        {
            start = i+1;
            hash.clear();
        }
    }
}

// Driver Code
int main()
{
    string str = "aeoibsddaeiouudb";
    FindSubstring(str);
    return 0;
}

Java

// Java program to find all substring that
// contain all vowels
import java.util.HashSet;

public class GFG {

    // Returns true if x is vowel.
    static boolean isVowel(char x) {
        // Function to check whether a character is
        // vowel or not
        return (x == 'a' || x == 'e' || x == 'i'
                || x == 'o' || x == 'u');
    }

    // Function to FindSubstrings of string
    static void findSubstring(String str) {
        HashSet<Character> hash = new HashSet<Character>();
        // To store vowels

        int start = 0;
        for (int i = 0; i < str.length(); i++) {
            // If current character is vowel then
            // insert into hash ,
            if (isVowel(str.charAt(i)) == true) {
                hash.add(str.charAt(i));

                // If all vowels are present in current
                // substring
                if (hash.size() == 5)
                    System.out.print(str.substring(start, i + 1) + " ");
            } else {
                start = i + 1;
                hash.clear();
            }
        }
    }

    // Driver Code
    public static void main(String[] args) {
        String str = "aeoibsddaeiouudb";
        findSubstring(str);
    }

}

Python3

# Python3 program to find all substring
# that contain all vowels

# Returns true if x is vowel.
def isVowel(x):

    # Function to check whether
    # a character is vowel or not
    return (x == 'a' or x == 'e' or
            x == 'i' or x == 'o' or
            x == 'u');

# Function to FindSubstrings of string
def FindSubstring(str):

    hash = set(); # To store vowels

    start = 0;
    for i in range(len(str)):

        # If current character is vowel
        # then insert into hash
        if (isVowel(str[i]) == True):
            hash.add(str[i]);

            # If all vowels are present
            # in current substring
            if (len(hash) == 5):
                print(str[start : i + 1],
                              end = " ");
        else:
            start = i + 1;
            hash.clear();

# Driver Code
str = "aeoibsddaeiouudb";
FindSubstring(str);

# This code is contributed by 29AjayKumar

C#

using System;
using System.Collections.Generic;

// c# program to find all substring that
// contain all vowels

public class GFG
{

    // Returns true if x is vowel.
    public static bool isVowel(char x)
    {
        // Function to check whether a character is
        // vowel or not
        return (x == 'a' || x == 'e' || x == 'i' || x == 'o' || x == 'u');
    }

    // Function to FindSubstrings of string
    public static void findSubstring(string str)
    {
        HashSet<char> hash = new HashSet<char>();
        // To store vowels

        int start = 0;
        for (int i = 0; i < str.Length; i++)
        {
            // If current character is vowel then
            // insert into hash ,
            if (isVowel(str[i]) == true)
            {
                hash.Add(str[i]);

                // If all vowels are present in current
                // substring
                if (hash.Count == 5)
                {
                    Console.Write(str.Substring(start, (i + 1) - start) + " ");
                }
            }
            else
            {
                start = i + 1;
                hash.Clear();
            }
        }
    }

    // Driver Code
    public static void Main(string[] args)
    {
        string str = "aeoibsddaeiouudb";
        findSubstring(str);
    }

}

// This code is contributed by Shrikant13

Javascript

<script>

// Javascript program to find all substring that
// contain all vowels

// Returns true if x is vowel.
function isVowel(x)
{

    // Function to check whether a character is
    // vowel or not
    return (x == 'a' || x == 'e' || x == 'i' ||
            x == 'o' || x == 'u');
}

// Function to FindSubstrings of string
function findSubstring(str)
{
    let hash = new Set();

    // To store vowels
    let start = 0;
    for(let i = 0; i < str.length; i++)
    {

        // If current character is vowel then
        // insert into hash ,
        if (isVowel(str[i]) == true)
        {
            hash.add(str[i]);

            // If all vowels are present in current
            // substring
            if (hash.size == 5)
                document.write(
                    str.substring(start, i + 1) + " ");
        }
        else
        {
            start = i + 1;
            hash.clear();
        }
    }
}

// Driver Code
let str = "aeoibsddaeiouudb";
findSubstring(str);

// This code is contributed by unknown2108

</script>

Output

aeiou aeiouu 

Time Complexity: O(n)
Auxiliary Space: O(1), the algorithm uses a HashSet to store the vowels, but the size of the HashSet is always 5 regardless of the length of the input string so it use constant space

Thanks to Kriti Shukla for suggesting this optimized solution.