Submission #958610

#	Time	Username	Problem	Language	Result	Execution time	Memory
958610		pcc	Three Friends (BOI14_friends)	C++17	100 / 100	8 ms	8252 KiB

friends

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fs first
#define sc second
#define tlll tuple<ll,ll,ll>


const int mxn = 2e6+10;
int n;
string s;
string ans;

int main(){
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	cin>>n>>s;
	if(n%2==0){
		cout<<"NOT POSSIBLE\n";
		return 0;
	}
	string ts = s.substr(0,n/2);
	int pt = 0;
	for(int i = n/2;i<n;i++){
		if(pt != ts.size()&&s[i] == ts[pt])pt++;
	}
	if(pt == ts.size())ans = ts;
	ts = s.substr(n-n/2,n/2);
	pt = 0;
	for(int i = 0;i<=n/2;i++){
		if(pt != ts.size()&&ts[pt] == s[i])pt++;
	}
	if(pt == ts.size()){
		if(pt =!ans.empty()&&ans != ts){
			cout<<"NOT UNIQUE\n";
			return 0;
		}
		ans = ts;
	}
	cout<<(ans.empty()?"NOT POSSIBLE":ans)<<'\n';
}

Compilation message (stderr)

friends.cpp: In function 'int main()':
friends.cpp:27:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |   if(pt != ts.size()&&s[i] == ts[pt])pt++;
      |      ~~~^~~~~~~~~~~~
friends.cpp:29:8: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |  if(pt == ts.size())ans = ts;
      |     ~~~^~~~~~~~~~~~
friends.cpp:33:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |   if(pt != ts.size()&&ts[pt] == s[i])pt++;
      |      ~~~^~~~~~~~~~~~
friends.cpp:35:8: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |  if(pt == ts.size()){
      |     ~~~^~~~~~~~~~~~
friends.cpp:36:9: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   36 |   if(pt =!ans.empty()&&ans != ts){
      |      ~~~^~~~~~~~~~~~~~~~~~~~~~~~

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