Submission #990727

#	Time	Username	Problem	Language	Result	Execution time	Memory
990727		Khanhcsp2	Three Friends (BOI14_friends)	C++14	100 / 100	14 ms	8468 KiB

friends

#include <bits/stdc++.h>
#define el '\n'
#define fi first
#define sc second
#define int ll
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
const int mod=1e9+7;
const int N=1e5+11;
string s, s1="", s2="";
int n;
void sol()
{
    cin >> n >> s;
    s=" "+s;
    if(n%2==0)
    {
        cout << "NOT POSSIBLE";
        return;
    }
    else
    {
        int i=1, j=n/2+2, ans=0, ch=0;
        while(i<=n/2+1)
        {
            if(ch==2) break;
            if(s[i]==s[j]) s1+=s[i], i++, j++;
            else i++, ch++;
        }
        if(ch<=1) ans++;
        i=1, j=n/2+1, ch=0;
        while(i<=n/2)
        {
            if(ch==2) break;
            if(s[i]==s[j]) s2+=s[j], i++, j++;
            else j++, ch++;
        }
        if(ch<=1) ans++;
        string ss=s1;
        if(s2.size()==n/2) ss=s2;
        if(ans==2 && s1!=s2) cout << "NOT UNIQUE";
        else if(ans>=1) cout << ss;
        else cout << "NOT POSSIBLE";
    }
}
signed main()
{
//    freopen("divisor.INP", "r", stdin);
//    freopen("divisor.OUT", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t=1;
    //cin >> t;
    while(t--)
    {
        sol();
    }
}

Compilation message (stderr)

friends.cpp: In function 'void sol()':
friends.cpp:44:21: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
   44 |         if(s2.size()==n/2) ss=s2;
      |            ~~~~~~~~~^~~~~

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