Score : $300$ points

问题描述

你将得到一个长度为 $N$ 的字符串 $S$，其中包含小写英文字母、, 和 "。保证 $S$ 中包含偶数个 "。

令 $2K$ 表示 $S$ 中的 " 总数。对于每个 $i=1,2,\ldots,K$，从第 $(2i-1)$ 个 " 到第 $(2i)$ 个 " 的字符被视为 被包围 的字符。

你的任务是将 $S$ 中所有 未被包围 的 , 替换为 .，并输出变换后的字符串。

以上为通义千问 qwen-max 翻译，仅供参考。

Problem Statement

You are given a string $S$ of length $N$ consisting of lowercase English letters, ,, and ". It is guaranteed that $S$ contains an even number of ".

Let $2K$ be the number of " in $S$. For each $i=1,2,\ldots,K$, the characters from the $(2i-1)$-th " through the $(2i)$-th " are said to be enclosed.

Your task is to replace each , in $S$ that is not an enclosed character with . and print the resulting string.

Constraints

• $N$ is an integer between $1$ and $2\times 10^5$, inclusive.
• $S$ is a string of length $N$ consisting of lowercase English letters, ,, and ".
• $S$ contains an even number of ".

Input

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

$N$

$S$

Output

Print the answer.

Sample Input 1

8
"a,b"c,d

Sample Output 1

"a,b"c.d

In $S$, "a,b" are enclosed characters, and c,d are not.

The , in $S$ that is not an enclosed character is the seventh character from the left in $S$, so replace that character with . to get the answer.

Sample Input 2

5
,,,,,

Sample Output 2

.....

Sample Input 3

20
a,"t,"c,"o,"d,"e,"r,

Sample Output 3

a."t,"c."o,"d."e,"r.

update @ 2024/3/10 11:49:56