程设2023期末

A.围栏

#include <iostream>
using namespace std;
int main(){
	long long n, ans = 0;cin>>n;
	for(long long i = 1; i <= n; ++i){
		long long tmp = (n + i - 1) / i;
		if (tmp < i) break;
		ans = max(ans, (i + tmp) * 2);
	}cout<<ans<<endl;
	return 0;
}

B.解密

#include <iostream>
#include <cstdio>

using namespace std;

string solve(string a){
	int len = a.length();
	int mid = (len + 1) / 2;
	if (len <= 2) return a;
	string str1(a, 1, mid - 1), str2(a, mid, len - mid), str3(a, 0, 1);
	return solve(str1) + str3 + solve(str2);
}

int main(){
	string a;cin>>a;
	cout<<solve(a)<<endl;
	return 0;
}

String语法