Interview Course Based on Story Questions

# Problem statement

Given a string, find the length of the longest substring `T` that contains at most `k` distinct characters.

## Input

The input will contain a string `s` and an integer `k`. The following is an example input:

```python
"cdaba", 3
```


## Output
The output will be an integer representing the length of the longest substring. The following is an example output:

```python
4
```
The substring `daba` is the longest string in the above input that has 3 distinct characters.


# Coding exercise

Implement the `length_of_longest_substring_k_distinct(s, k)` function, where `s` is the string and `k` is the integer. The function returns the length of the longest substring that has `k` distinct characters.




DIY: Longest Substring with At Most K Distinct Characters

Problem statement