Score : $600$ points

问题描述

给定一个由 Y 和 . 组成的字符串 $S$。

你可以在 $0$ 到 $K$ 次（包含）之间对 $S$ 执行以下操作：

• 交换 $S$ 中的两个相邻字符。

在执行操作后，$S$ 中连续 Ys 的最大可能数量是多少？

以上为通义千问 qwen-max 翻译，仅供参考。

Problem Statement

Given is a string $S$ consisting of Y and ..

You can do the following operation on $S$ between $0$ and $K$ times (inclusive).

• Swap two adjacent characters in $S$.

What is the maximum possible number of consecutive Ys in $S$ after the operations?

Constraints

• $2 \leq |S| \leq 2 \times 10^5$
• Each character of $S$ is Y or ..
• $0 \leq K \leq 10^{12}$
• $K$ is an integer.

Input

Input is given from Standard Input in the following format:

$S$

$K$

Output

Print the answer.

Sample Input 1

YY...Y.Y.Y.
2

Sample Output 1

3

After swapping the $6$-th, $7$-th characters, and $9$-th, $10$-th characters, we have YY....YYY.., which has three consecutive Ys at $7$-th through $9$-th positions.
We cannot have four or more consecutive Ys, so the answer is $3$.

Sample Input 2

YYYY....YYY
3

Sample Output 2

4

update @ 2024/3/10 10:01:53