Score : $100$ points

问题描述

你将得到一个由小写英文字母组成的长度为偶数的字符串 $S$。设 $|S|$ 表示字符串 $S$ 的长度，$S_i$ 表示字符串 $S$ 中的第 $i$ 个字符。

按照以下顺序对每个 $i = 1, 2, \ldots, \frac{|S|}{2}$ 执行以下操作，并打印最终的 $S$：

• 将 $S_{2i-1}$ 和 $S_{2i}$ 交换位置。

以上为通义千问 qwen-max 翻译，仅供参考。

Problem Statement

You are given a string $S$ of even length consisting of lowercase English letters. Let $|S|$ be the length of $S$, and $S_i$ be the $i$-th character of $S$.

Perform the following operation for each $i = 1, 2, \ldots, \frac{|S|}{2}$ in this order, and print the final $S$.

• Swap $S_{2i-1}$ and $S_{2i}$.

Constraints

• $S$ is a string of even length consisting of lowercase English letters.
• The length of $S$ is at most $100$.

Input

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

$S$

Output

Print the answer.

Sample Input 1

abcdef

Sample Output 1

badcfe

Initially, $S =$ abcdef.
Performing the operation for $i = 1$ swaps $S_1$ and $S_2$, making $S =$ bacdef.
Performing the operation for $i = 2$ swaps $S_3$ and $S_4$, making $S =$ badcef.
Performing the operation for $i = 3$ swaps $S_5$ and $S_6$, making $S =$ badcfe.
Thus, badcfe should be printed.

Sample Input 2

aaaa

Sample Output 2

aaaa

Sample Input 3

atcoderbeginnercontest

Sample Output 3

taocedbrgeniencrnoetts

update @ 2024/3/10 12:11:58