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Submission #925174

# Submission time Handle Problem Language Result Execution time Memory
925174 2024-02-10T23:20:38 Z NintsiChkhaidze Three Friends (BOI14_friends) C++17
100 / 100
 54 ms 40528 KB 
#include <bits/stdc++.h>
#define ll long long
#define s second
#define f first
#define pb push_back
#define pii pair <int,int>
#define left (h<<1),l,(l + r)/2
#define right ((h<<1)|1),(l + r)/2 + 1,r
#define int ll
using namespace std;
 
const int N = 2e6 + 3,mod = 1e9 + 7;
 
int h[N],pwr[N],cnt[30];
 
signed main(){
	ios_base::sync_with_stdio(0),cin.tie(NULL),cout.tie(NULL);
 
	pwr[0] = 1;
	for (int i = 1; i <= 2000001; i++)
		pwr[i] = (pwr[i - 1] * 31) % mod;
 
	int n;
	cin>>n;
 
	string s;
	cin>>s;
 
	s= '%'+s;
	for (int i = 1; i <= n; i++){
		h[i] = h[i - 1] + pwr[i] * (s[i] - 'A' + 1) % mod;
		h[i] %= mod;
		cnt[s[i] - 'A' + 1]++;
	}
 
	int id = 0;
	for (int i = 1; i <= 26; i++){
		if (cnt[i] % 2 == 1){
			if (id) {
				cout<<"NOT POSSIBLE"<<endl;
				exit(0);
			}
			id = i;
		}
	}
	
	if (!id) {
		cout<<"NOT POSSIBLE"<<endl;
		exit(0);
	}
 
	set <int> st;
	string ans = "";
 
	for (int i = 1; i <= n; i++){
		if (id != s[i] - 'A' + 1) continue;
 
		int hash1 = 0,hash2 = 0;
		int len = (n - 1)/2,p1=0,p2=0;
 
		if (len >= i){
			hash1 = h[i - 1] * 31 + (h[len + 1] - h[i]);
			hash1 %= mod; hash1 += mod; hash1 %= mod;
 
			hash2 = h[n] - h[len + 1]; hash2 += mod; hash2 %= mod;
			p2 = len+2; p1 = 2;
		}else{
			hash1 = h[len]; p1 = 1; p2 = len + 2;
			hash2 = (h[i - 1] - h[len]) * 31 + (h[n] - h[i]);
			hash2 %= mod; hash2 += mod; hash2 %= mod;	
		}
 
		int mx = max(p1,p2);
		hash1 *= pwr[mx-p1];
		hash2 *= pwr[mx-p2];
 
		if (hash1 % mod == hash2 % mod) {
			int sz=st.size();
			st.insert(hash1 % mod);
			if (st.size() > 1) {
				cout<<"NOT UNIQUE"<<endl;
				exit(0);
			}
			if (sz == 1) continue;
			
			if (len < i) {
				for (int j = 1; j <= len; j++)
					ans += s[j];
			}else{
				for (int j = n; j >= n - len + 1; j--){
					ans += s[j];
				}
				reverse(ans.begin(),ans.end());
			}
		}
	}
	
	if (st.size()) cout<<ans;
	else cout<<"NOT POSSIBLE"<<endl;
}

Subtask #1
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 16988 KB Output is correct
2 Correct 10 ms 16984 KB Output is correct
3 Correct 11 ms 16988 KB Output is correct
4 Correct 10 ms 16988 KB Output is correct
5 Correct 10 ms 16988 KB Output is correct
6 Correct 10 ms 16984 KB Output is correct
7 Correct 10 ms 16988 KB Output is correct
8 Correct 10 ms 16988 KB Output is correct
9 Correct 11 ms 17028 KB Output is correct
10 Correct 11 ms 16988 KB Output is correct
11 Correct 10 ms 16988 KB Output is correct
12 Correct 11 ms 16988 KB Output is correct
13 Correct 10 ms 16988 KB Output is correct
14 Correct 10 ms 16984 KB Output is correct
15 Correct 11 ms 16984 KB Output is correct
16 Correct 10 ms 17016 KB Output is correct
17 Correct 11 ms 16984 KB Output is correct
18 Correct 10 ms 16988 KB Output is correct
19 Correct 10 ms 16984 KB Output is correct
20 Correct 10 ms 17028 KB Output is correct
21 Correct 10 ms 16984 KB Output is correct
22 Correct 10 ms 16988 KB Output is correct
23 Correct 11 ms 16988 KB Output is correct
24 Correct 10 ms 16988 KB Output is correct
25 Correct 10 ms 16984 KB Output is correct
26 Correct 10 ms 16988 KB Output is correct
27 Correct 10 ms 16988 KB Output is correct
28 Correct 10 ms 16984 KB Output is correct
29 Correct 10 ms 16988 KB Output is correct
30 Correct 10 ms 16984 KB Output is correct
31 Correct 10 ms 16984 KB Output is correct
32 Correct 11 ms 16988 KB Output is correct
33 Correct 11 ms 17244 KB Output is correct
34 Correct 10 ms 16988 KB Output is correct
35 Correct 10 ms 16984 KB Output is correct
36 Correct 10 ms 16988 KB Output is correct
37 Correct 10 ms 16988 KB Output is correct
38 Correct 10 ms 16984 KB Output is correct
39 Correct 10 ms 16988 KB Output is correct
40 Correct 10 ms 16988 KB Output is correct
41 Correct 10 ms 16988 KB Output is correct
42 Correct 11 ms 16988 KB Output is correct
43 Correct 10 ms 16984 KB Output is correct
44 Correct 10 ms 16988 KB Output is correct
45 Correct 10 ms 17036 KB Output is correct
46 Correct 10 ms 16984 KB Output is correct
47 Correct 10 ms 16988 KB Output is correct
48 Correct 10 ms 16984 KB Output is correct
49 Correct 10 ms 16988 KB Output is correct
50 Correct 10 ms 16988 KB Output is correct
51 Correct 10 ms 17024 KB Output is correct
52 Correct 10 ms 16984 KB Output is correct
53 Correct 10 ms 16988 KB Output is correct
54 Correct 10 ms 16988 KB Output is correct

Subtask #2
65.0 / 65.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 39504 KB Output is correct
2 Correct 39 ms 40528 KB Output is correct
3 Correct 38 ms 39508 KB Output is correct
4 Correct 40 ms 39548 KB Output is correct
5 Correct 37 ms 39496 KB Output is correct
6 Correct 28 ms 35664 KB Output is correct
7 Correct 54 ms 39500 KB Output is correct
8 Correct 35 ms 36580 KB Output is correct
9 Correct 36 ms 37652 KB Output is correct
10 Correct 35 ms 37676 KB Output is correct
11 Correct 29 ms 32664 KB Output is correct
12 Correct 11 ms 16988 KB Output is correct
13 Correct 10 ms 16984 KB Output is correct
14 Correct 10 ms 16988 KB Output is correct
15 Correct 10 ms 16988 KB Output is correct
16 Correct 11 ms 16984 KB Output is correct
17 Correct 10 ms 16988 KB Output is correct
18 Correct 10 ms 17048 KB Output is correct
19 Correct 11 ms 16988 KB Output is correct
20 Correct 10 ms 16984 KB Output is correct
21 Correct 10 ms 17044 KB Output is correct
22 Correct 10 ms 16988 KB Output is correct
23 Correct 10 ms 16988 KB Output is correct
24 Correct 10 ms 16988 KB Output is correct
25 Correct 11 ms 16988 KB Output is correct
26 Correct 10 ms 16988 KB Output is correct
27 Correct 10 ms 16988 KB Output is correct
28 Correct 10 ms 16988 KB Output is correct
29 Correct 10 ms 16988 KB Output is correct
30 Correct 11 ms 17028 KB Output is correct
31 Correct 10 ms 16984 KB Output is correct
32 Correct 10 ms 16988 KB Output is correct
33 Correct 11 ms 16988 KB Output is correct
34 Correct 10 ms 17016 KB Output is correct
35 Correct 10 ms 16988 KB Output is correct
36 Correct 10 ms 16988 KB Output is correct
37 Correct 10 ms 16988 KB Output is correct
38 Correct 10 ms 17048 KB Output is correct
39 Correct 10 ms 16988 KB Output is correct
40 Correct 10 ms 16988 KB Output is correct
41 Correct 10 ms 16984 KB Output is correct
42 Correct 10 ms 16988 KB Output is correct
43 Correct 11 ms 16988 KB Output is correct
44 Correct 11 ms 16988 KB Output is correct
45 Correct 11 ms 16996 KB Output is correct
46 Correct 10 ms 16800 KB Output is correct
47 Correct 10 ms 16988 KB Output is correct
48 Correct 10 ms 17048 KB Output is correct
49 Correct 10 ms 16988 KB Output is correct
50 Correct 10 ms 16988 KB Output is correct
51 Correct 10 ms 17040 KB Output is correct
52 Correct 10 ms 16988 KB Output is correct
53 Correct 11 ms 16988 KB Output is correct
54 Correct 10 ms 17240 KB Output is correct