Submission #931227

#	Time	Username	Problem	Language	Result	Execution time	Memory
931227		Bzslayed	Three Friends (BOI14_friends)	C++17	100 / 100	11 ms	10244 KiB

friends

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
 
using namespace std;
using namespace __gnu_pbds; 
 
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
 
#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define pff pair<float, float>
#define coutpair(p) cout << p.first << " " << p.second << "\n"
 
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_multiset;
 
int main(){
    ios_base::sync_with_stdio(0); 
    cin.tie(0); 
    cout.tie(0);
 
    int n; cin >> n;
    string s; cin >> s;

    if (n%2==0 || n < 3){
		cout << "NOT POSSIBLE";
		return 0;
	}

    set<string> st;
    string s1, s2;

    int mid = n/2;
    for (int i=mid+1; i<n; i++) s1 += s[i];
    
    int p1, p2;
    for(p1=0; p1<mid; p1++){
		if (s[p1] != s1[p1]) break;
	}
	for(p2=mid; p2>0; p2--){
		if (s[p2] != s1[p2-1]) break;
	}

	if (p1 >= p2) st.insert(s1);
	for (int i=0; i<mid; i++) s2 += s[i];
    for (p1=mid; p1<n-1; p1++){
		if (s[p1] != s2[p1-mid]) break;
	}
	for(p2=n-1; p2>mid; p2--){
		if (s[p2] != s2[p2-1-mid]) break;
	}
	if (p1 >= p2) st.insert(s2);
	if (st.size() > 1) cout << "NOT UNIQUE";
	else if (st.size() == 1) cout << *st.begin();
	else cout << "NOT POSSIBLE";
    return 0;
}

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