Submission #853156

#	Time	Username	Problem	Language	Result	Execution time	Memory
853156		NK_	Three Friends (BOI14_friends)	C++17	100 / 100	18 ms	9776 KiB

friends

// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
 
using namespace std;
 
#define nl '\n'
#define pb push_back
#define pf push_front
 
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
 
template<class T> using V = vector<T>;
using pi = pair<int, int>;
using vi = V<int>;
using vpi = V<pi>;
 
using ll = long long;
using pl = pair<ll, ll>;
using vpl = V<pl>;
using vl = V<ll>;
 
using db = long double;
 
template<class T> using pq = priority_queue<T, V<T>, greater<T>>;
 
const int MOD = 1e9 + 7;
const ll INFL = ll(1e17);
const int LG = 18;

int main() {
	cin.tie(0)->sync_with_stdio(0);

	int N; cin >> N;
	string S; cin >> S;

	if (N % 2 == 0) {
		cout << "NOT POSSIBLE" << nl;
		exit(0-0);
	}

	int M = (N - 1) / 2;

	auto tri = [&](string T) {

		int j = 0;
		for(int i = 0; i < N; i++) {
			if (j < 2*M && S[i] == T[j]) j++;
		}

		return j == 2 * M;
	};

	string A = S.substr(0, M);
	string B = S.substr(N - M, M);

	if (A == B) B.back() = '|';

	bool a = tri(A + A), b = tri(B + B);
	
	if (a && b) cout << "NOT UNIQUE" << nl;
	else if (a) cout << A << nl;
	else if (b) cout << B << nl;
	else cout << "NOT POSSIBLE" << nl;



	exit(0-0);
} 	

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