AtCoder ABC 306 解析

原创

已于 2023-06-21 21:18:53 修改 · 586 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#c++

于 2023-06-21 21:18:46 首次发布

文章提供了四个不同的编程问题，涉及字符串重复、二进制序列计算、数组排序以及基于状态的动态规划解题策略。每个问题都包含输入输出示例和解决方案的思路，适合提升编程和算法能力。

A - Echo

B - Base 2

C - Centers

D - Poisonous Full-Course

A - Echo

Time Limit: 2 sec / Memory Limit: 1024 MB

Score : 100100 points

Problem Statement

You are given a string SS of length NN consisting of lowercase English letters.
We denote the ii-th character of SS by S_iSi.
Print the string of length 2N2N obtained by concatenating S_1,S_1,S_2,S_2,\dots,S_NS1,S1,S2,S2,…,SN, and S_NSN in this order.
For example, if SS is beginner, print bbeeggiinnnneerr.

Constraints

NN is an integer such that 1 \le N \le 501≤N≤50.
SS is a string of length NN consisting of lowercase English letters.

Input

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

NN
SS

Output

Print the answer.

Sample Input 1

8
beginner

Sample Output 1

bbeeggiinnnneerr

It is the same as the example described in the problem statement.

Sample Input 2

Copy

3
aaa

Sample Output 2

Copy

aaaaaa

可以定义一个变量来存储要打印的字符串，但在竞争性编程中，所需的只是正确的输出，因此您可以放松并实现以下内容：

用for语句迭代S的每个字符，并打印两次。

在这里，您必须小心，不要打印不必要的空格或换行符。

#include<bits/stdc++.h>

using namespace std;

int main(){
  int n;
  string s;
  cin >> n >> s;
  for(int i=0;i<n;i++){
    cout << s[i] << s[i];
  }cout << "\n";
  return 0;
}