Submission #930637

#	Time	Username	Problem	Language	Result	Execution time	Memory
930637		zyq181	Three Friends (BOI14_friends)	C++17	100 / 100	39 ms	4764 KiB

friends

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

int N;
char c;
char ok[2000010];
int pt;
bool ans1, ans2;

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> N;
	if(!(N%2)){
		cout << "NOT POSSIBLE";
		return 0;
	}
	int k = N/2;
	for(int a=1; a<=N; a++){
		cin >> ok[a];
	}
	ans1 = ans2 = true;
	pt = k+1;
	for(int a=1; a<=k; a++){
		while(pt != N+1 && ok[pt] != ok[a]) {
			pt++;
		}
		if(pt == N+1){
			ans1 = false;
			break;
		}
		pt++;
	}
	pt = 1;
	for(int a=k+2; a<=N; a++){
		while(pt != k+2 && ok[pt] != ok[a]) {
			pt++;
		}
		if(pt == k+2){
			ans2 = false;
			break;
		}
		pt++;
	}
	if(ans1 && ans2){
		for(int a=1; a<=k; a++){
			if(ok[a] != ok[a+k+1]){
				cout << "NOT UNIQUE";
				return 0;
			}
		}
		for(int a=1; a<=k; a++){
			cout << ok[a];
		}
	}
	else if(ans1){
		for(int a=1; a<=k; a++){
			cout << ok[a];
		}
	}
	else if(ans2){
		for(int a=k+2; a<=N; a++){
			cout << ok[a];
		}
	}
	else{
		cout << "NOT POSSIBLE";
	}
}

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