# 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=3Output :ABCABCABCAExplanation:The output string has 3 distinct characters.

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

**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 <bits/stdc++.h>` `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` |

## Javascript

`<script>` ` ` `// Javascript Program to Find the` ` ` `// String having each substring` ` ` `// with exactly K distinct characters` ` ` ` ` `// Function to find the` ` ` `// required output string` ` ` `function` `findString(N, K)` ` ` `{` ` ` ` ` `// Each element at index` ` ` `// i is modulus of K` ` ` `for` `(let i = 0; i < N; i++)` ` ` `{` ` ` `document.write(String.fromCharCode(` `'A'` `.charCodeAt() + i % K));` ` ` `}` ` ` `}` ` ` ` ` `// initialise integers N and K` ` ` `let N = 10;` ` ` `let K = 3;` ` ` ` ` `findString(N, K);` `// This code is contributed by divyesh072019.` `</script>` |

**Output:**

ABCABCABCA

**Time Complexity:**O(N)**Auxiliary Space: **O(1)