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답안 #957531

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
957531 2024-04-04T01:21:17 Z YassirSalama 세 명의 친구들 (BOI14_friends) C++17
100 / 100
 268 ms 37612 KB 
#include <bits/stdc++.h>
using namespace std;
const int dx[4] = {1,0,-1,0}, dy[4] = {0,1,0,-1};
#define OVL(x,s) for(auto y:x) cout<<y<<s; cout<<"\n";
#ifdef IOI
void dbg_out() { cout << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cout << ' ' << H; dbg_out(T...); }
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__);
#else
#define dbg(...) 1337;
#endif
#define endl "\n"
#define pb push_back
#define F first
#define S second
#define ll long long
#define mod 1000000007
#define all(v) v.begin(),v.end()
#define int long long
const int MAXN=2e6+100,P=31;
int binpow(int a,int b){
	int res=1;
	while(b){
		if(b&1) res=(res%mod*a%mod)%mod;
		a=(a%mod*a%mod)%mod;
		b>>=1LL;
	}
	return res%mod;
}
int invmod(int a){
	return binpow(a,mod-2)%mod;
}
int pref[MAXN];
int inv[MAXN];
int sum(int l,int r){
	if(l==0) return pref[r]%mod;
	else 
		return ((pref[r]-pref[l-1]+2LL*mod)%mod*(inv[l]%mod))%mod;
}
signed main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
int n;
cin>>n;
string s;
cin>>s;
if(n%2==0){
	cout<<"NOT POSSIBLE"<<endl;
	return 0;
}
inv[0]=1;
inv[1]=invmod(P);
for(int i=2;i<MAXN;i++){
	inv[i]=(inv[i-1]%mod*(inv[1]%mod))%mod;
}
int c=1;
memset(pref,0,sizeof(pref));
for(int i=0;i<n;i++){
	int x=s[i]-'A'+1;
	if(i) pref[i]=pref[i-1];
	pref[i]%=mod;
	pref[i]+=(x%mod*c%mod)%mod;
	c=(c%mod*P%mod)%mod;
}
map<int,pair<int,int>> mp;
vector<pair<int,int>> ans;
for(int i=0;i<n;i++){
	int l1=0,r1=0,l2=0,r2=n-1;
	if(i==0){
		l1=1;
	}
	if(i==n-1){
		r2=n-2;
	}
	r1=l1+(n-2)/2;
	if(i>0&&i<=r1) r1++;
	l2=r2-(n-2)/2;
	if(i!=n-1&&i>=l2) l2--;
	if((i>r1&&i<l2)||i==0||i==n-1){
		if(sum(l1,r1)==sum(l2,r2)) mp[sum(l1,r1)]={l1,r1};
		else continue;
	}
	if(i<=r1){
		int t=i-1;
		int t1=i+1;
		int s=0;
		s+=sum(l1,t);
		s%=mod;
		s+=binpow(P,(i%((n-2)/2+1)))*sum(t1,r1);
		s%=mod;
		s+=mod;
		s%=mod;
		if(s==sum(l2,r2)%mod) mp[s]={l2,r2};
	}else{
		int t=i-1;
		int t1=i+1;
		int s=0;
		s+=sum(l2,t);
		s%=mod;
		s+=binpow(P,(i%((n-2)/2+1)))*sum(t1,r2);
		s%=mod;
		s+=mod;
		s%=mod;
		if(s==sum(l1,r1)) mp[s]={l1,r1};
	}
}
if(mp.size()==1){
	pair<int,int> anss=mp.begin()->second;
	cout<<s.substr(anss.F,anss.S-anss.F+1)<<endl;
}else{
	if(mp.empty()){
		cout<<"NOT POSSIBLE"<<endl;
		return 0;
	}
	cout<<"NOT UNIQUE"<<endl;
	return 0;
}
 
}

Subtask #1
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 18 ms 31580 KB Output is correct
2 Correct 14 ms 31616 KB Output is correct
3 Correct 13 ms 31580 KB Output is correct
4 Correct 13 ms 31580 KB Output is correct
5 Correct 14 ms 31604 KB Output is correct
6 Correct 16 ms 31620 KB Output is correct
7 Correct 13 ms 31660 KB Output is correct
8 Correct 14 ms 31580 KB Output is correct
9 Correct 13 ms 31576 KB Output is correct
10 Correct 13 ms 31836 KB Output is correct
11 Correct 13 ms 31576 KB Output is correct
12 Correct 13 ms 31608 KB Output is correct
13 Correct 13 ms 31580 KB Output is correct
14 Correct 13 ms 31580 KB Output is correct
15 Correct 14 ms 31628 KB Output is correct
16 Correct 14 ms 31624 KB Output is correct
17 Correct 13 ms 31576 KB Output is correct
18 Correct 13 ms 31832 KB Output is correct
19 Correct 13 ms 31580 KB Output is correct
20 Correct 13 ms 31580 KB Output is correct
21 Correct 13 ms 31580 KB Output is correct
22 Correct 13 ms 31580 KB Output is correct
23 Correct 13 ms 31576 KB Output is correct
24 Correct 0 ms 348 KB Output is correct
25 Correct 0 ms 348 KB Output is correct
26 Correct 0 ms 344 KB Output is correct
27 Correct 13 ms 31576 KB Output is correct
28 Correct 13 ms 31580 KB Output is correct
29 Correct 13 ms 31616 KB Output is correct
30 Correct 14 ms 31664 KB Output is correct
31 Correct 13 ms 31580 KB Output is correct
32 Correct 13 ms 31580 KB Output is correct
33 Correct 13 ms 31580 KB Output is correct
34 Correct 13 ms 31620 KB Output is correct
35 Correct 13 ms 31632 KB Output is correct
36 Correct 13 ms 31580 KB Output is correct
37 Correct 13 ms 31580 KB Output is correct
38 Correct 14 ms 31576 KB Output is correct
39 Correct 13 ms 31580 KB Output is correct
40 Correct 13 ms 31576 KB Output is correct
41 Correct 13 ms 31580 KB Output is correct
42 Correct 13 ms 31612 KB Output is correct
43 Correct 13 ms 31576 KB Output is correct
44 Correct 13 ms 31608 KB Output is correct
45 Correct 13 ms 31576 KB Output is correct
46 Correct 13 ms 31580 KB Output is correct
47 Correct 13 ms 31576 KB Output is correct
48 Correct 14 ms 31580 KB Output is correct
49 Correct 0 ms 348 KB Output is correct
50 Correct 14 ms 31632 KB Output is correct
51 Correct 13 ms 31576 KB Output is correct
52 Correct 13 ms 31580 KB Output is correct
53 Correct 13 ms 31632 KB Output is correct
54 Correct 13 ms 32088 KB Output is correct

Subtask #2
65.0 / 65.0

# 결과 실행 시간 메모리 Grader output
1 Correct 251 ms 35648 KB Output is correct
2 Correct 259 ms 37588 KB Output is correct
3 Correct 252 ms 37612 KB Output is correct
4 Correct 251 ms 37448 KB Output is correct
5 Correct 268 ms 37588 KB Output is correct
6 Correct 4 ms 4348 KB Output is correct
7 Correct 259 ms 37584 KB Output is correct
8 Correct 225 ms 35284 KB Output is correct
9 Correct 229 ms 36940 KB Output is correct
10 Correct 237 ms 36848 KB Output is correct
11 Correct 207 ms 35060 KB Output is correct
12 Correct 13 ms 31628 KB Output is correct
13 Correct 13 ms 31580 KB Output is correct
14 Correct 13 ms 31580 KB Output is correct
15 Correct 13 ms 31620 KB Output is correct
16 Correct 13 ms 31580 KB Output is correct
17 Correct 13 ms 31580 KB Output is correct
18 Correct 13 ms 31580 KB Output is correct
19 Correct 13 ms 31832 KB Output is correct
20 Correct 14 ms 31580 KB Output is correct
21 Correct 13 ms 31580 KB Output is correct
22 Correct 13 ms 31576 KB Output is correct
23 Correct 13 ms 31616 KB Output is correct
24 Correct 13 ms 31580 KB Output is correct
25 Correct 13 ms 31580 KB Output is correct
26 Correct 14 ms 31628 KB Output is correct
27 Correct 13 ms 31576 KB Output is correct
28 Correct 14 ms 31640 KB Output is correct
29 Correct 13 ms 31576 KB Output is correct
30 Correct 13 ms 31580 KB Output is correct
31 Correct 13 ms 31580 KB Output is correct
32 Correct 13 ms 31576 KB Output is correct
33 Correct 13 ms 31580 KB Output is correct
34 Correct 13 ms 31628 KB Output is correct
35 Correct 0 ms 348 KB Output is correct
36 Correct 0 ms 348 KB Output is correct
37 Correct 0 ms 348 KB Output is correct
38 Correct 13 ms 31624 KB Output is correct
39 Correct 13 ms 31580 KB Output is correct
40 Correct 13 ms 31576 KB Output is correct
41 Correct 14 ms 31576 KB Output is correct
42 Correct 13 ms 31580 KB Output is correct
43 Correct 13 ms 31576 KB Output is correct
44 Correct 13 ms 31580 KB Output is correct
45 Correct 13 ms 31576 KB Output is correct
46 Correct 13 ms 31624 KB Output is correct
47 Correct 13 ms 31580 KB Output is correct
48 Correct 13 ms 31580 KB Output is correct
49 Correct 13 ms 31640 KB Output is correct
50 Correct 13 ms 31580 KB Output is correct
51 Correct 13 ms 31628 KB Output is correct
52 Correct 13 ms 31580 KB Output is correct
53 Correct 13 ms 31832 KB Output is correct
54 Correct 13 ms 31580 KB Output is correct