Submission #930759

#	Time	Username	Problem	Language	Result	Execution time	Memory
930759		Pwo	Three Friends (BOI14_friends)	C++17	0 / 100	36 ms	6092 KiB

friends

#include <bits/stdc++.h>
using namespace std;
 
int32_t main() {
    int n; cin >> n; string s; cin >> s;
    if (n % 2 == 0) { cout << "NOT POSSIBLE"; return 0; }
    
    int mp1[26]{}, mp2[26]{}; int l = (n - 1) / 2;
    for (int i = 0; i < n; i++) {
        int chr = (s[i] - 'A');
        if (i < l) mp1[chr]++;
        else mp2[chr]++;
    }
    
    int d1 = 0; for (int i = 0; i < 26; i++) d1 += abs(mp1[i] - mp2[i]);
    
    fill(mp1, mp1 + 26, 0); fill(mp2, mp2 + 26, 0); l = (n + 1) / 2;
    for (int i = 0; i < n; i++) {
        int chr = (s[i] - 'A');
        if (i < l) mp1[chr]++;
        else mp2[chr]++;
    }
    
    int d2 = 0; for (int i = 0; i < 26; i++) d2 += abs(mp1[i] - mp2[i]);
 
    if (d1 == 1 && d2 == 1) cout << "NOT UNIQUE";
    else if (d1 == 1) {
		int diff = 0, a = 0, b = l - 1;
		while (a < l - 1) {
			if (s[a] != s[b]) {
				diff++, b++;
				if (diff == 2) break;
			} a++, b++;
		}
		if (diff == 2) cout << "NOT POSSIBLE";
		else cout << s.substr(0, (n - 1) / 2);
    } else if (d2 == 1) {
		int diff = 0, a = 0, b = l;
		while (b < n) {
			if (s[a] != s[b]) {
				diff++, a++;
				if (diff == 2) break;
			} a++, b++;
		}
		if (diff == 2) cout << "NOT POSSIBLE";
		else cout << s.substr((n + 1) / 2, (n - 1) / 2);
	}
    else cout << "NOT POSSIBLE";
}

• Subtask 1: 0 / 35
• Subtask 2: 0 / 65