# Encrypt string with product of number of vowels and consonants in substring of size k

Given a string s and a positive integer k. You need to encrypt the given string such that each substring of size k is represented by an integer, which is obtained by the product of number of vowels and number of consonants in the substring.

Examples:

```Input : s = "hello", k = 2
Output : 1101
k = 2, so each substring should be of size 2,
he, consonants = 1, vowels = 1, product = 1
el, consonants = 1, vowels = 1, product = 1
ll, consonants = 1, vowels = 0, product = 0
lo, consonants = 1, vowels = 1, product = 1
So, encrypted string is 1101.

Input : s = "geeksforgeeks", k = 5
Output : 666446666```

Method 1 (Brute Force): The idea is to find each substring of size k and calculate the number of vowels and consonants, and then store the product of two.

Implementation:

## C++

 `// CPP Program to Encrypt string with product` `// of number of vowels and consonants in every` `// substring of size k` `#include ` `using` `namespace` `std;`   `// isVowel() is a function that returns true` `// for a vowel and false otherwise.` `bool` `isVowel(``char` `c)` `{` `    ``return` `(c == ``'a'` `|| c == ``'e'` `|| c == ``'i'` `||` `            ``c == ``'o'` `|| c == ``'u'``);` `}`   `// function to Encrypt the string` `string encryptString(string s, ``int` `n, ``int` `k)` `{` `    ``int` `countVowels = 0;` `    ``int` `countConsonants = 0;` `    ``string ans = ``""``;`   `    ``// for each substring` `    ``for` `(``int` `l = 0; l <= n - k; l++) {` `        ``countVowels = 0;` `        ``countConsonants = 0;`   `        ``// substring of size k` `        ``for` `(``int` `r = l; r <= l + k - 1; r++) {`   `            ``// counting number of vowels and` `            ``// consonants` `            ``if` `(isVowel(s[r]) == ``true``)` `                ``countVowels++;` `            ``else` `                ``countConsonants++;` `        ``}`   `        ``// append product to answer.` `        ``ans += to_string(countVowels * countConsonants);` `    ``}` `    ``return` `ans;` `}`   `// Driven Program` `int` `main()` `{` `    ``string s = ``"hello"``;` `    ``int` `n = s.length();` `    ``int` `k = 2;` `    ``cout << encryptString(s, n, k) << endl;` `    ``return` `0;` `}`

## Java

 `// Java Program to Encrypt String with product ` `// of number of vowels and consonants in every ` `// substring of size k `   `class` `GFG {`   `// isVowel() is a function that returns true ` `// for a vowel and false otherwise. ` `    ``static` `boolean` `isVowel(``char` `c) {` `        ``return` `(c == ``'a'` `|| c == ``'e'` `|| c == ``'i'` `                ``|| c == ``'o'` `|| c == ``'u'``);` `    ``}`   `// function to Encrypt the string ` `    ``static` `String encryptString(String s, ``int` `n, ``int` `k) {` `        ``int` `countVowels = ``0``;` `        ``int` `countConsonants = ``0``;` `        ``String ans = ``""``;`   `        ``// for each substring ` `        ``for` `(``int` `l = ``0``; l <= n - k; l++) {` `            ``countVowels = ``0``;` `            ``countConsonants = ``0``;`   `            ``// substring of size k ` `            ``for` `(``int` `r = l; r <= l + k - ``1``; r++) {`   `                ``// counting number of vowels and ` `                ``// consonants ` `                ``if` `(isVowel(s.charAt(r)) == ``true``) {` `                    ``countVowels++;` `                ``} ``else` `{` `                    ``countConsonants++;` `                ``}` `            ``}`   `            ``// append product to answer. ` `            ``ans += String.valueOf(countVowels * countConsonants);` `        ``}` `        ``return` `ans;` `    ``}`   `// Driven Program ` `    ``static` `public` `void` `main(String[] args) {` `        ``String s = ``"hello"``;` `        ``int` `n = s.length();` `        ``int` `k = ``2``;` `        ``System.out.println(encryptString(s, n, k));` `    ``}` `}`   `// This code is contributed by 29AjayKumar`

## Python3

 `# Python Program to Encrypt string with ` `# product of number of vowels and ` `# consonants in every substring of size k`   `# isVowel() is a function that returns ` `# true for a vowel and false otherwise.` `def` `isVowel(c):` `    ``return` `(c ``=``=` `'a'` `or` `c ``=``=` `'e'` `or` `            ``c ``=``=` `'i'` `or` `c ``=``=` `'o'` `or` `            ``c ``=``=` `'u'``)`   `# function to Encrypt the string` `def` `encryptString(s, n, k):` `    ``countVowels ``=` `0` `    ``countConsonants ``=` `0` `    ``ans ``=` `""`   `    ``# for each substring` `    ``for` `l ``in` `range``(n ``-` `k ``+` `1``):` `        ``countVowels ``=` `0` `        ``countConsonants ``=` `0`   `        ``# substring of size k` `        ``for` `r ``in` `range``(l, l ``+` `k):`   `            ``# counting number of vowels ` `            ``# and consonants` `            ``if` `(isVowel(s[r]) ``=``=` `True``):` `                ``countVowels ``+``=` `1` `            ``else``:` `                ``countConsonants ``+``=` `1` `                `  `        ``# append product to answer` `        ``ans ``+``=` `(``str``)(countVowels ``*` `                     ``countConsonants)` `    ``return` `ans`   `# Driver Code` `if` `__name__ ``=``=` `'__main__'``:` `    ``s ``=` `"hello"` `    ``n ``=` `len``(s)` `    ``k ``=` `2` `    ``print``(encryptString(s, n, k))`   `# This code is contributed ` `# by PrinciRaj1992`

## C#

 `// C# Program to Encrypt String with product ` `// of number of vowels and consonants in every ` `// substring of size k ` `using` `System;` `                    `  `public` `class` `GFG {` ` `  `// isVowel() is a function that returns true ` `// for a vowel and false otherwise. ` `    ``static` `bool` `isVowel(``char` `c) {` `        ``return` `(c == ``'a'` `|| c == ``'e'` `|| c == ``'i'` `                ``|| c == ``'o'` `|| c == ``'u'``);` `    ``}` ` `  `// function to Encrypt the string ` `    ``static` `String encryptString(String s, ``int` `n, ``int` `k) {` `        ``int` `countVowels = 0;` `        ``int` `countConsonants = 0;` `        ``String ans = ``""``;` ` `  `        ``// for each substring ` `        ``for` `(``int` `l = 0; l <= n - k; l++) {` `            ``countVowels = 0;` `            ``countConsonants = 0;` ` `  `            ``// substring of size k ` `            ``for` `(``int` `r = l; r <= l + k - 1; r++) {` ` `  `                ``// counting number of vowels and ` `                ``// consonants ` `                ``if` `(isVowel(s[r]) == ``true``) {` `                    ``countVowels++;` `                ``} ``else` `{` `                    ``countConsonants++;` `                ``}` `            ``}` ` `  `            ``// append product to answer. ` `            ``ans += Convert.ToString(countVowels * countConsonants);` `        ``}` `        ``return` `ans;` `    ``}`   `// Driven Program ` `    ``static` `public` `void` `Main() {` `        ``String s = ``"hello"``;` `        ``int` `n = s.Length;` `        ``int` `k = 2;` `        ``Console.Write(encryptString(s, n, k));` `    ``}` `}` ` `  `// This code is contributed by 29AjayKumar`

## PHP

 `

## Javascript

 ``

Output

`1101`

Method 2 (Efficient Approach):

The above approach can be optimized. In above approach, we are calculating whether a character is vowel or consonant more than one times. Now, taking a closer look at it, we can see that we are calculating the count of vowels and consonants for the same k – 1 characters twice. We can calculate the count of vowels and consonants for the characters from [1….k – 1] and [2….k-1] twice.
To avoid this, we can precompute the count of vowels and consonants till each index i and later use those values to calculate the result.

Below is the implementation of this approach:

## C++

 `// CPP Program to Encrypt string with product of ` `// number of vowels and consonants in substring` `// of size k` `#include ` `using` `namespace` `std;`   `// isVowel() is a function that returns true` `// for a vowel and false otherwise.` `bool` `isVowel(``char` `c)` `{` `    ``return` `(c == ``'a'` `|| c == ``'e'` `|| c == ``'i'` `||` `            ``c == ``'o'` `|| c == ``'u'``);` `}`   `// function to Encrypt the string` `string encryptString(string s, ``int` `n, ``int` `k)` `{` `    ``// cv to count vowel` `    ``// cc to count consonants` `    ``int` `cv[n], cc[n];`   `    ``if` `(isVowel(s[0]))` `        ``cv[0] = 1;` `    ``else` `        ``cc[0] = 1;`   `    ``// Counting prefix count of vowel` `    ``// and prefix count of consonants` `    ``for` `(``int` `i = 1; i < n; i++) {` `        ``cv[i] = cv[i - 1] + isVowel(s[i]);` `        ``cc[i] = cc[i - 1] + !isVowel(s[i]);` `    ``}`   `    ``string ans = ``""``;` `    ``int` `prod = 0;`   `    ``prod = cc[k - 1] * cv[k - 1];` `    ``ans += to_string(prod);`   `    ``// generating the encrypted string.` `    ``for` `(``int` `i = k; i < s.length(); i++) {` `        ``prod = (cc[i] - cc[i - k]) * (cv[i] - cv[i - k]);` `        ``ans += to_string(prod);` `    ``}`   `    ``return` `ans;` `}` `// Driven Program` `int` `main()` `{` `    ``string s = ``"hello"``;` `    ``int` `n = s.length();` `    ``int` `k = 2;`   `    ``cout << encryptString(s, n, k) << endl;` `    ``return` `0;` `}`

## Java

 `// JAVA Program to Encrypt String with product of ` `// number of vowels and consonants in subString` `// of size k` `class` `GFG ` `{`   `    ``// isVowel() is a function that returns true` `    ``// for a vowel and false otherwise.` `    ``static` `boolean` `isVowel(``char` `c) ` `    ``{` `        ``return` `(c == ``'a'` `|| c == ``'e'` `||` `                ``c == ``'i'` `|| c == ``'o'` `|| ` `                ``c == ``'u'``);` `    ``}`   `    ``// function to Encrypt the String` `    ``static` `String encryptString(``char``[] s, ``int` `n, ``int` `k)` `    ``{` `        ``// cv to count vowel` `        ``// cc to count consonants` `        ``int``[] cv = ``new` `int``[n];` `        ``int``[] cc = ``new` `int``[n];`   `        ``if` `(isVowel(s[``0``]))` `            ``cv[``0``] = ``1``;` `        ``else` `            ``cc[``0``] = ``1``;`   `        ``// Counting prefix count of vowel` `        ``// and prefix count of consonants` `        ``for` `(``int` `i = ``1``; i < n; i++)` `        ``{` `            ``cv[i] = cv[i - ``1``] + (isVowel(s[i]) == ``true` `? ``1` `: ``0``);` `            ``cc[i] = cc[i - ``1``] + (isVowel(s[i]) == ``true` `? ``0` `: ``1``);` `        ``}`   `        ``String ans = ``""``;` `        ``int` `prod = ``0``;`   `        ``prod = cc[k - ``1``] * cv[k - ``1``];` `        ``ans += String.valueOf(prod);`   `        ``// generating the encrypted String.` `        ``for` `(``int` `i = k; i < s.length; i++) ` `        ``{` `            ``prod = (cc[i] - cc[i - k]) * ` `                   ``(cv[i] - cv[i - k]);` `            ``ans += String.valueOf(prod);` `        ``}` `        ``return` `ans;` `    ``}`   `    ``// Driver Code` `    ``public` `static` `void` `main(String[] args) ` `    ``{` `        ``String s = ``"hello"``;` `        ``int` `n = s.length();` `        ``int` `k = ``2``;`   `        ``System.out.print(encryptString(s.toCharArray(), n, k) + ``"\n"``);` `    ``}` `}`   `// This code is contributed by 29AjayKumar`

## Python3

 `# Python 3 Program to Encrypt string with ` `# product of number of vowels and consonants ` `# in substring of size k`   `# isVowel() is a function that returns true` `# for a vowel and false otherwise.` `def` `isVowel(c):` `    ``return` `(c ``=``=` `'a'` `or` `c ``=``=` `'e'` `or` `            ``c ``=``=` `'i'` `or` `c ``=``=` `'o'` `or` `c ``=``=` `'u'``)`   `# function to Encrypt the string` `def` `encryptString(s, n, k):` `    `  `    ``# cv to count vowel` `    ``# cc to count consonants` `    ``cv ``=` `[``0` `for` `i ``in` `range``(n)]` `    ``cc ``=` `[``0` `for` `i ``in` `range``(n)]`   `    ``if` `(isVowel(s[``0``])):` `        ``cv[``0``] ``=` `1` `    ``else``:` `        ``cc[``0``] ``=` `1`   `    ``# Counting prefix count of vowel` `    ``# and prefix count of consonants` `    ``for` `i ``in` `range``(``1``,n):` `        ``cv[i] ``=` `cv[i ``-` `1``] ``+` `isVowel(s[i])` `        ``cc[i] ``=` `cc[i ``-` `1``] ``+` `(isVowel(s[i]) ``=``=` `False``)`   `    ``ans ``=` `""` `    ``prod ``=` `0`   `    ``prod ``=` `cc[k ``-` `1``] ``*` `cv[k ``-` `1``]` `    ``ans ``+``=` `str``(prod)`   `    ``# generating the encrypted string.` `    ``for` `i ``in` `range``(k, ``len``(s)):` `        ``prod ``=` `((cc[i] ``-` `cc[i ``-` `k]) ``*` `                ``(cv[i] ``-` `cv[i ``-` `k]))` `        ``ans ``+``=` `str``(prod)`   `    ``return` `ans`   `# Driver Code` `if` `__name__ ``=``=` `'__main__'``:` `    ``s ``=` `"hello"` `    ``n ``=` `len``(s)` `    ``k ``=` `2`   `    ``print``(encryptString(s, n, k))` `    `  `# This code is contributed by` `# Surendra_Gangwar`

## C#

 `// C# Program to Encrypt String with ` `// product of number of vowels and ` `// consonants in subString of size k` `using` `System;`   `class` `GFG ` `{`   `    ``// isVowel() is a function that` `    ``// returns true for a vowel and ` `    ``// false otherwise.` `    ``static` `bool` `isVowel(``char` `c) ` `    ``{` `        ``return` `(c == ``'a'` `|| c == ``'e'` `||` `                ``c == ``'i'` `|| c == ``'o'` `|| ` `                ``c == ``'u'``);` `    ``}`   `    ``// function to Encrypt the String` `    ``static` `String encryptString(``char``[] s, ` `                         ``int` `n, ``int` `k)` `    ``{` `        ``// cv to count vowel` `        ``// cc to count consonants` `        ``int``[] cv = ``new` `int``[n];` `        ``int``[] cc = ``new` `int``[n];`   `        ``if` `(isVowel(s[0]))` `            ``cv[0] = 1;` `        ``else` `            ``cc[0] = 1;`   `        ``// Counting prefix count of vowel` `        ``// and prefix count of consonants` `        ``for` `(``int` `i = 1; i < n; i++)` `        ``{` `            ``cv[i] = cv[i - 1] + ` `                   ``(isVowel(s[i]) == ``true` `? 1 : 0);` `            ``cc[i] = cc[i - 1] + ` `                   ``(isVowel(s[i]) == ``true` `? 0 : 1);` `        ``}`   `        ``String ans = ``""``;` `        ``int` `prod = 0;`   `        ``prod = cc[k - 1] * cv[k - 1];` `        ``ans += String.Join(``""``, prod);`   `        ``// generating the encrypted String.` `        ``for` `(``int` `i = k; i < s.Length; i++) ` `        ``{` `            ``prod = (cc[i] - cc[i - k]) * ` `                   ``(cv[i] - cv[i - k]);` `            ``ans += String.Join(``""``, prod);` `        ``}` `        ``return` `ans;` `    ``}`   `    ``// Driver Code` `    ``public` `static` `void` `Main(String[] args) ` `    ``{` `        ``String s = ``"hello"``;` `        ``int` `n = s.Length;` `        ``int` `k = 2;`   `        ``Console.Write(encryptString(` `                      ``s.ToCharArray(), n, k) + ``"\n"``);` `    ``}` `}`   `// This code is contributed by 29AjayKumar`

## Javascript

 ``

Output

`-1355847807101`

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