Score : $200$ points

问题描述

在一场编程竞赛的资格赛中，共有 $N$ 名参赛者。所有参赛者的排名各不相同。

您将得到一个长度为 $N$ 的字符串 $S$，表示参赛者是否愿意参加决赛。具体规则如下：

• 如果字符串 $S$ 的第 $i$ 个字符是 o，则资格赛排名第 $i$ 的参赛者希望参加决赛；
• 如果字符串 $S$ 的第 $i$ 个字符是 x，则资格赛排名第 $i$ 的参赛者不愿参加决赛。

在所有希望参加决赛的选手中，排名最小的 $K$ 位选手将晋级决赛。

请输出一个长度为 $N$ 的字符串 $T$，满足以下条件：

• 如果资格赛排名第 $i$ 的选手晋级决赛，则字符串 $T$ 的第 $i$ 个字符为 o；
• 如果资格赛排名第 $i$ 的选手未能晋级决赛，则字符串 $T$ 的第 $i$ 个字符为 x。

以上为通义千问 qwen-max 翻译，仅供参考。

Problem Statement

There were $N$ contestants in the qualification round of a programming contest. All contestants got distinct ranks.
You are given a length-$N$ string $S$, which represents whether the contestants want to participate in the final round or not. Specifically,

• if the $i$-th character of $S$ is o, the contestant ranked $i$-th in the qualification wants to participate in the final;
• if the $i$-th character of $S$ is x, the contestant ranked $i$-th in the qualification does not want to participate in the final.

Among those who want to participate in the final, $K$ contestants with the smallest ranks advance to the final.

Print a string $T$ of length $N$ that satisfies the following conditions:

• if the contestant ranked $i$-th in the qualification advances to the final, the $i$-th character of $T$ is o;
• if the contestant ranked $i$-th in the qualification does not advance to the final, the $i$-th character of $T$ is x.

Constraints

• $N$ and $K$ are integers.
• $1 \le K \le N \le 100$
• $S$ is a string of length $N$ consisting of o and x.
• $S$ has at least $K$ o's.

Input

The input is given from Standard Input in the following format:

$N$ $K$

$S$

Output

Print the answer.

Sample Input 1

10 3
oxxoxooxox

Sample Output 1

oxxoxoxxxx

In this input, $N=10$ people took part in the qualification round, and $K=3$ of them advance to the final.

• The participant who ranked $1$-st in the qualification wants to participate in the final, so the participant advances to the final. $1$ participant has advanced so far.
• The participants who ranked $2$-nd and $3$-rd in the qualification do not want to participate in the final, so the participants do not advance to the final.
• The participant who ranked $4$-th in the qualification wants to participate in the final, so the participant advances to the final. $2$ participants have advanced so far.
• The participants who ranked $5$-th in the qualification does not want to participate in the final, so the participant does not advance to the final.
• The participant who ranked $6$-th in the qualification wants to participate in the final, so the participant advances to the final. $3$ participants have advanced so far.
• Now that $3$ people have advanced to the final, no participants ranked $7$-th or lower advance to the final.

update @ 2024/3/10 12:06:32