Submission #1093114

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093114		juicy	Three Friends (BOI14_friends)	C++17	100 / 100	10 ms	10260 KiB

friends

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

bool check(string s, string r) {
  int n = r.size();
  for (int i = 0, j = -1; i < n; ++i) {
    if (j++ == n) {
      return 0;
    }
    while (s[j] != r[i]) {
      if (j++ == n) {
        return 0;
      }
    }
  }
  return 1;
}

int main() {
  ios::sync_with_stdio(false); cin.tie(nullptr);

  int n; string s; cin >> n >> s;
  if (n % 2 == 0) {
    cout << "NOT POSSIBLE";
    exit(0);
  }
  set<string> st;
  string l = s.substr(0, n / 2), r = s.substr(n / 2, n / 2 + 1);
  if (check(r, l)) {
    st.insert(l);
  }
  l = s.substr(0, n / 2 + 1), r = s.substr(n / 2 + 1, n / 2);
  if (check(l, r)) {
    st.insert(r);
  }
  cout << (!st.size() ? "NOT POSSIBLE" : (st.size() == 1 ? *st.begin() : "NOT UNIQUE"));
  return 0;
}

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