Submission #727440

#	Time	Username	Problem	Language	Result	Execution time	Memory
727440		AdamGS	Three Friends (BOI14_friends)	C++17	100 / 100	39 ms	9524 KiB

friends

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
bool check(string s, string u) {
	int l=0, ile=0;
	for(auto i : s) {
		if(i==u[l]) {
			++l;
			ile+=l/u.size();
			l%=u.size();
		}
	}
	return ile>=2;
}
int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	int n;
	string s;
	cin >> n >> s;
	if(n%2==0) {
		cout << "NOT POSSIBLE\n";
		return 0;
	}
	string a="", b="";
	rep(i, n/2) {
		a+=s[i];
		b+=s[(n+1)/2+i];
	}
	bool ok1=check(s, a), ok2=check(s, b);
	if(ok1 && ok2 && a!=b) {
		cout << "NOT UNIQUE\n";
		return 0;
	}
	if(!ok1 && !ok2) {
		cout << "NOT POSSIBLE\n";
		return 0;
	}
	cout << (ok1?a:b) << '\n';
}

• Subtask 1: 35 / 35
• Subtask 2: 65 / 65