Longest Uniform Answer Block After Limited Changes
Company: Amazon
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Other
### Problem
The string `answerKey` contains only `T` and `F`. You may change at most `k` positions to either symbol. Return the largest length of a contiguous block that can contain one repeated symbol after those changes.
```cpp
class Solution {
public:
int maxConsecutiveAnswers(string answerKey, int k);
};
```
### Examples
**Example 1:**
```text
answerKey = "FTFTF", k = 1
Output: 3
Explanation: Changing the middle T in a length-three FTF block creates FFF; every length-four block needs two changes.
```
**Example 2:**
```text
answerKey = "FFTTF", k = 2
Output: 5
Explanation: Changing both T symbols makes the entire string F.
```
### Constraints
- `1 <= answerKey.length <= 5 * 10^4`.
- Characters are T or F; `1 <= k <= answerKey.length`.
### Clarifying Questions
The goal is one contiguous run and the budget is at most k, not exactly k.
```hint Inspect the structure
For a fixed desired symbol, how many characters in a window must change?
```
### Reasoning checkpoints
- Find the longest achievable contiguous run for either symbol while staying within the change budget.
- Distinguish at most k changes from exactly k and justify that no longer feasible block is missed.
### Optional extensions
Can you obtain the answer in one pass while allowing either target symbol?
Overview: Longest Uniform Answer Block After Limited Changes. The string answerKey contains only T and F. Change at most k positions to either symbol. Return the greatest possible length of a contiguous block containing one repeated symbol after the changes.
