Submission #1026588

#	Time	Username	Problem	Language	Result	Execution time	Memory
1026588		hasan2006	Three Friends (BOI14_friends)	C++17	100 / 100	15 ms	26880 KiB

friends

#include <bits/stdc++.h>

using namespace std;

#define TL ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define rall(s) s.rbegin(),s.rend()
#define all(s) s.begin(),s.end()
#define pb push_back
#define se second
#define fi first
#define ll long long
#define ld long double
#define YES cout<<"YES\n"
#define Yes cout<<"Yes\n"
#define yes cout<<"yes\n"
#define NO cout<<"NO\n"
#define No cout<<"No\n"
#define no cout<<"no\n"


const int N = 2e6 + 9 , mod = 1e9 + 7;
ll  b[N] ,  c[N];

void solve()
{
    ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
    cin>>n;
    string a;
    cin>>a;
    if(n % 2 == 0){
        cout<<"NOT POSSIBLE";
        return;
    }
    set<int>st;
    if(a.substr(1 , n / 2) == a.substr(1 + n / 2 , n / 2)){
        st.insert(1);
    }
    if(a.substr(0 , n / 2) == a.substr(n / 2 , n / 2)){
        st.insert(0);
    }
    if(a.substr(0 , n / 2) == a.substr(n / 2 + 1 , n / 2)){
            st.insert(0);
    }
    r =  n ;
    for(i = n / 2; i >= 0; i--)
        b[i] = ((a[i] == a[--r]) && (i == n / 2 || b[i + 1]));
    r  = n / 2;
    for(i = 0; i <= n / 2; i++)
        c[i] = ((a[i] == a[++r]) && (i == 0 || c[i - 1]));
    for(i = 1; i < n / 2; i++)
        if(b[i + 1] && c[i - 1]){
            st.insert(n / 2 + 1);
            break;
        }
    string d = a;
    a = a.substr(n / 2  , n / 2 + 1) + a.substr(0 , n / 2);
    r =  n ;
    for(i = n / 2; i >= 0; i--)
        b[i] = ((a[i] == a[--r]) && (i == n / 2 || b[i + 1]));
    r  = n / 2;
    for(i = 0; i <= n / 2; i++)
        c[i] = ((a[i] == a[++r]) && (i == 0 || c[i - 1]));
    for(i = 1; i < n / 2; i++)
        if(b[i + 1] && c[i - 1]){
            st.insert(0);
            break;
        }
    set<string>ss;
    for(auto it : st)
        ss.insert(d.substr(it , n / 2));
    if(ss.size() == 1)
        cout<<*ss.begin();
    else if(!ss.size())
        cout<<"NOT POSSIBLE";
    else
        cout<<"NOT UNIQUE";
}

int main(){
    TL;

    /*#ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif*/
    int t = 1;
//    cin>>t;
    while(t--)
     {
        solve();
     }
}
// Author : حسن

Compilation message (stderr)

friends.cpp: In function 'void solve()':
friends.cpp:26:12: warning: unused variable 'q' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |            ^
friends.cpp:26:20: warning: unused variable 'j' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                    ^
friends.cpp:26:23: warning: unused variable 'l' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                       ^
friends.cpp:26:30: warning: unused variable 'x' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                              ^
friends.cpp:26:34: warning: unused variable 'y' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                                  ^
friends.cpp:26:38: warning: unused variable 's' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                                      ^
friends.cpp:26:46: warning: unused variable 'f' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                                              ^
friends.cpp:26:50: warning: unused variable 'k' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                                                  ^
friends.cpp:26:54: warning: unused variable 'm' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                                                      ^
friends.cpp:26:58: warning: unused variable 'mn' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                                                          ^~
friends.cpp:26:69: warning: unused variable 'mx' [-Wunused-variable]
   26 |     ll n , q , i , j ,l ,r , x , y , s = 0 , f , k , m , mn = 1e18, mx = 0 ;
      |                                                                     ^~

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