Submission #931292

#	Time	Username	Problem	Language	Result	Execution time	Memory
931292		Bulbasheen	Three Friends (BOI14_friends)	C++14	100 / 100	25 ms	5284 KiB

friends

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define all(x) x.begin(), x.end()

int N, pt, a;
char U[2000010];
bool front, back, uni;

int32_t main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> N;
    if (N%2 == 0){
        cout << "NOT POSSIBLE";
        return 0;
    }
    cin >> U;
    pt = (N-1)/2;
    a = 0;
    front = true;
    while (a < (N-1)/2){
        if (pt > N-1){
            front = false;
            break;
        }
        if (U[pt] != U[a]){
            pt++;
            continue;
        }
        else {
            pt++;
            a++;
        }
    }
    pt = 0;
    a = (N+1)/2;
    back = true;
    while (a < N){
        if (pt > (N-1)/2){
            back = false;
            break;
        }
        if (U[pt] != U[a]){
            pt++;
            continue;
        }
        else{
            pt++;
            a++;
        }
    }
    if (back and front){
        for (int i = 0; i < (N-1)/2; i++){
            if (U[i] != U[i+(N+1)/2]){
                cout << "NOT UNIQUE";
                return 0;
            }
        }
        for (int i = 0; i < (N-1)/2; i++){
            cout << U[i];
        }
    }
    else if (!back and !front){
        cout << "NOT POSSIBLE";
    }
    else if (front){
        for (int i = 0; i < (N-1)/2; i++){
            cout << U[i];
        }
    }
    else{
        for (int i = (N+1)/2; i < N; i++){
            cout << U[i];
        }
    }
}

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