Submission #1026212

#	Time	Username	Problem	Language	Result	Execution time	Memory
1026212		VMaksimoski008	Three Friends (BOI14_friends)	C++17	100 / 100	52 ms	12808 KiB

friends

#include <bits/stdc++.h>

#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
//#define int long long

using namespace std;

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;

string check(string s) {
    int n = s.size();
    int len = (n - 1) / 2;
    
    string A = "";
    for(int i=0; i<len; i++) A += s[i];
    string B = "";
    for(int i=len; i<n; i++) {
        if(s[i] == A[B.size()]) B += s[i];
    }

    // cout << A << " " << B << '\n';
    if(A == B) return A;
    return "-1";
}

signed main() {
    int n;
    cin >> n;

    if(n % 2 == 0) {
        cout << "NOT POSSIBLE\n";
        return 0;
    }

    string s;
    cin >> s;

    string A = check(s);
    reverse(s.begin(), s.end());
    string B = check(s);

    if(A == "-1" && B == "-1") {
        cout << "NOT POSSIBLE\n";
    } else if(B == "-1") {
        cout << A << '\n';
    } else if(A == "-1") {
        reverse(B.begin(), B.end());
        cout << B << '\n';
    } else {
        reverse(B.begin(), B.end());
        if(A == B) cout << A << '\n';
        else cout << "NOT UNIQUE\n";
    }

    return 0;
}

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