题解 | #Hello World for U#

#include <cstdio>
#include <string>

using namespace std;

int main() {
	string str;
	while (cin >> str) {
		int len = str.size();
		int n1 = len / 2;
		int n2 = len - 2 * n1;
		while (n1 + 1 > n2) {
			n1--;
			n2 = len - 2 * n1;
		}
		int i = 0;
		while (i < n1) {
			cout << str[i];
			for(int j = 0; j < n2 - 2; j++) {
				cout << ' ';
			}
			cout << str[len-i-1] << endl;
			i++;
		}
		cout << str.substr(n1, n2) << endl;
	}
	return 0;
}