Submission #968746

#	Time	Username	Problem	Language	Result	Execution time	Memory
968746		youssef_3breheem	Three Friends (BOI14_friends)	C++17	100 / 100	9 ms	9312 KiB

friends

#include <bits/stdc++.h>
using namespace std;
#define LCBorz ios_base::sync_with_stdio(false); cin.tie(0);
#define all(x) x.begin(), x.end()
#define endl '\n'
const int N=200005;
const int INF=1e9;
string cmp(string a,string b){
    if(a.size()>b.size())swap(a,b);
    int bad=0;
    int j=0;
    int n=a.size();
    for(int i=0;i<n;i++){
        while(j<b.size()&&a[i]!=b[j]){
            bad++;
            j++;
        }
        j++;
    }
    return (bad<=1?a:"");
}
int32_t main() {
    LCBorz;
    int n;cin>>n;
    string s;cin>>s;
    string a=cmp(s.substr(0,n/2),s.substr(n/2,n-n/2));
    string b=cmp(s.substr(0,n/2+1),s.substr(n/2+1,n-n/2));
    if(n%2==0||(a.size()==0&&b.size()==0)){
        cout<<"NOT POSSIBLE"<<endl;
        return 0;
    }
    if(a.size()!=0&&b.size()!=0&&a!=b){
        cout<<"NOT UNIQUE"<<endl;
        return 0;
    }
    cout<<(a.size()?a:b)<<endl;
 
 
    return 0;
}

Compilation message (stderr)

friends.cpp: In function 'std::string cmp(std::string, std::string)':
friends.cpp:14:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |         while(j<b.size()&&a[i]!=b[j]){
      |               ~^~~~~~~~~

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