Submission #203290

#	Time	Username	Problem	Language	Result	Execution time	Memory
203290		blacktulip	Three Friends (BOI14_friends)	C++17	100 / 100	39 ms	7576 KiB

friends

#include <bits/stdc++.h>
 
using namespace std;
 
#define fio() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
 
int n,m,b[200005],a[200005],k,flag,t,mpp[50],one,cev;
char c;
string s,ss,yaz,s1,s2;
vector<int> v;
 
int main(void){
	fio();
	cin>>n>>s;
	if(n%2==0){cout<<"NOT POSSIBLE\n";return 0;}
	for(int i=0;i<n;i++){
		mpp[s[i]-'A']++;
	}
	for(int i=0;i<=25;i++){
		if(mpp[i]%2){
			cev++;
			c=i+'A';
		}
	}
	for(int i=0;i<n/2;i++)s1+=s[i];
	for(int i=n/2+1;i<n;i++)s2+=s[i];
	if(cev!=1){cout<<"NOT POSSIBLE\n";return 0;}
	int bas=0;
	int son=n/2;
	cev=0;
	while(son<n){
		if(s[bas]!=s[son] && s[son]==c && flag==0){
			son++;
			flag=1;
		}
		else if(s[bas]!=s[son]){flag=2;break;}
		else{bas++;son++;}
	}
	if(flag!=2){
		cev++;
		one=1;
	}
	flag=0;
	bas=n/2;
	son=n-1;
	if(s1!=s2){
		while(bas>=0){
			//~ cout<<s[bas]<<" ;; "<<s[son]<<endl;
			if(s[bas]!=s[son] && s[bas]==c && flag==0){
				bas--;
				flag=1;
			}
			else if(s[bas]!=s[son]){flag=2;break;}
			else{bas--;son--;}
		}
		if(flag!=2)cev++;
	}
	
	if(cev==2){cout<<"NOT UNIQUE\n";return 0;}
	if(cev==0){cout<<"NOT POSSIBLE\n";return 0;}
	if(one==1){
		cout<<s1<<endl;
		return 0;
	}
	cout<<s2<<endl;
	return 0;
}

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