# Find the String having each substring with exactly K distinct characters

Given two integers N and K. The task is to find the string of length N, such that each substring of length greater than equal to K, has exactly K distinct characters.

Examples:

```Input: N=10, K=3
Output : ABCABCABCA
Explanation:
The output string has 3 distinct characters.

Input : N=20, K=7
Output : ABCDEFGABCDEFGABCDEF
Explanation:
The output string has 7 distinct characters.
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:

To solve the problem mentioned above the main idea is to print distinct elements up to length K, and then repeat the same elements up to N.

Below is the implementation of the above approach:

## C++

 `// C++ Program to Find the ` `// String having each substring ` `// with exactly K distinct characters ` `#include ` `using` `namespace` `std; ` ` `  `// Function to find the ` `// required output string ` `void` `findString(``int` `N, ``int` `K) ` `{ ` `    ``// Each element at index ` `    ``// i is modulus of K ` `    ``for` `(``int` `i = 0; i < N; i++) { ` ` `  `        ``cout << ``char``(``'A'` `+ i % K); ` `    ``} ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``// initialise integers N and K ` `    ``int` `N = 10; ` `    ``int` `K = 3; ` ` `  `    ``findString(N, K); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java program to find the ` `// string having each substring ` `// with exactly K distinct characters ` `import` `java.io.*;  ` ` `  `class` `GFG { ` ` `  `// Function to find the ` `// required output string ` `static` `void` `findString(``int` `N, ``int` `K) ` `{ ` `     `  `    ``// Each element at index ` `    ``// i is modulus of K ` `    ``for` `(``int` `i = ``0``; i < N; i++) ` `    ``{ ` `        ``System.out.print((``char``)(``'A'` `+ i % K)); ` `    ``} ` `} ` ` `  `// Driver code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``// Initialise integers N and K ` `    ``int` `N = ``10``; ` `    ``int` `K = ``3``; ` `    ``findString(N, K); ` `} ` `} ` ` `  `// This code is contributed by shivanisinghss2110`

## Python3

 `# Python3 Program to Find the  ` `# String having each substring  ` `# with exactly K distinct characters  ` ` `  `# Function to find the  ` `# required output string  ` `def` `findString(N, K) :  ` `    ``# Each element at index  ` `    ``# i is modulus of K  ` `    ``for` `i ``in` `range``(N) :  ` ` `  `        ``print``(``chr``(``ord``(``'A'``) ``+` `i ``%` `K),end``=``"");  ` ` `  `# Driver code  ` `if` `__name__ ``=``=` `"__main__"` `:  ` `    ``# initialise integers N and K  ` `    ``N ``=` `10``;  ` `    ``K ``=` `3``;  ` ` `  `    ``findString(N, K);  ` `     `  `# This code is contributed by AnkitRai01 `

## C#

 `// C# program to find the ` `// string having each substring ` `// with exactly K distinct characters ` `using` `System; ` ` `  `class` `GFG { ` ` `  `// Function to find the ` `// required output string ` `static` `void` `findString(``int` `N, ``int` `K) ` `{ ` `     `  `    ``// Each element at index ` `    ``// i is modulus of K ` `    ``for``(``int` `i = 0; i < N; i++) ` `    ``{ ` `       ``Console.Write((``char``)(``'A'` `+ i % K)); ` `    ``} ` `} ` ` `  `// Driver code ` `public` `static` `void` `Main(String[] args) ` `{ ` `     `  `    ``// Initialise integers N and K ` `    ``int` `N = 10; ` `    ``int` `K = 3; ` ` `  `    ``findString(N, K); ` `} ` `} ` ` `  `// This code is contributed by 29AjayKumar `

Output:

```ABCABCABCA
```

Time Complexity:O(N)

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