题解 | Hello World for U

#include <iostream>
#include <string>
#include <cmath>
using namespace std;
int main(){
    string str;
    while(cin >> str){
        int len = str.size();
        double k = (double)(len - 2) / (double)(3);
        int num;
        if(k - floor(k) >= 0.5){
            num = ceil(k);
        }else{
            num = floor(k);
        }        //确定从第几个字母折叠
        for(int i = 0; i < num; i ++){
            cout << str[i];
            for(int j = 0; j < len - 2 - 2 * num; j++){
                cout << " ";
            }
            cout << str[len - i -1] << endl;
        }
        for(int i = 0; i < len - 2 * num; i++){
            cout << str[num + i];
        }
        cout << endl;
    }

    return 0;
}