## **Problem Statement**

Given a string with lowercase letters only, if you are allowed to **replace no more than ‘k’ letters** with any letter, find the **length of the longest substring having the same letters** after replacement.

**Example 1:**

```
Input: str="aabccbb", k=2  
Output: 5  
Explanation: Replace the two 'c' with 'b' to have a longest repeating substring "bbbbb".
```

**Example 2:**

```
Input: str="abbcb", k=1  
Output: 4  
Explanation: Replace the 'c' with 'b' to have a longest repeating substring "bbbb".
```

**Example 3:**

```
Input: str="abccde", k=1  
Output: 3  
Explanation: Replace the 'b' or 'd' with 'c' to have the longest repeating substring "ccc".
```

**Constraints:**

- 1 <= str.length <= $10^5$
- `s` consists of only lowercase English letters.
- `0 <= k <= s.length`



## Try it yourself  
 Try solving this question here:

## **Problem Statement**
Given a string with lowercase letters only, if you are allowed to **replace no more than ‘k’ letters** with any letter, find the **length of the longest substring having the same letters** after replacement.

**Example 1:**

```
Input: String="aabccbb", k=2  
Output: 5  
Explanation: Replace the two 'c' with 'b' to have a longest repeating substring "bbbbb".
```

**Example 2:**

```
Input: String="abbcb", k=1  
Output: 4  
Explanation: Replace the 'c' with 'b' to have a longest repeating substring "bbbb".
```

**Example 3:**

```
Input: String="abccde", k=1  
Output: 3  
Explanation: Replace the 'b' or 'd' with 'c' to have the longest repeating substring "ccc".
```



## **Problem Statement**

Given a string with lowercase letters only, if you are allowed to **replace no more than ‘k’ letters** with any letter, find the **length of the longest substring having the same letters** after replacement.

**Example 1:**

```
Input: str="aabccbb", k=2  
Output: 5  
Explanation: Replace the two 'c' with 'b' to have a longest repeating substring "bbbbb".
```

**Example 2:**

```
Input: str="abbcb", k=1  
Output: 4  
Explanation: Replace the 'c' with 'b' to have a longest repeating substring "bbbb".
```

**Example 3:**

```
Input: str="abccde", k=1  
Output: 3  
Explanation: Replace the 'b' or 'd' with 'c' to have the longest repeating substring "ccc".
```

**Constraints:**

- 1 <= str.length <= $10^5$
- `s` consists of only uppercase English letters.
- `0 <= k <= s.length`

