/// dwuy: _,\,,,_\,__,\,,_
#include <bits/stdc++.h>
#define fastIO ios_base::sync_with_stdio(false); cin.tie(NULL)
#define file(a) freopen(a".inp","r",stdin); freopen(a".out", "w",stdout)
#define fi first
#define se second
#define endl "\n"
#define len(s) int32_t(s.length())
#define MASK(k)(1LL<<(k))
#define TASK ""
#define int long long
using namespace std;
typedef tuple<int, int, int> tpiii;
typedef pair<double, double> pdd;
typedef pair<int, int> pii;
typedef long long ll;
const long long OO = 1e18;
const int MOD1 = 998244353;
const int MOD2 = 1e9 + 7;
const int INF = 1e9;
const int MX = 2000005;
const int base = 307;
int n;
int pf1[MX];
int pf2[MX];
int bp1[MX];
int bp2[MX];
string s;
void nhap(){
cin >> n;
cin >> s;
if(!(n&1)){
cout << "NOT POSSIBLE";
exit(0);
}
}
int add1(int a, int b){
a += b;
return a + (a>=MOD1? -MOD1 : a<0? MOD1 : 0);
}
int mul1(int a, int b){
return a*b%MOD1;
}
int add2(int a, int b){
a += b;
return a + (a>=MOD2? -MOD2 : a<0? MOD2 : 0);
}
int mul2(int a, int b){
return a*b%MOD2;
}
int get1(int l, int r){
return add1(pf1[r], -mul1(pf1[l-1], bp1[r-l+1]));
}
int get2(int l, int r){
return add2(pf2[r], -mul2(pf2[l-1], bp2[r-l+1]));
}
void solve(){
s = ' ' + s;
bp1[0] = bp2[0] = 1;
for(int i=1; i<=n; i++){
bp1[i] = mul1(bp1[i-1], base);
bp2[i] = mul2(bp2[i-1], base);
}
for(int i=1; i<=n; i++){
pf1[i] = add1(mul1(pf1[i-1], base), s[i]);
pf2[i] = add2(mul2(pf2[i-1], base), s[i]);
}
int flag = -1;
int mid = (n+1)>>1;
bool isUnique = 1;
pii p = {-1, -1};
pii pre = {get1(1, mid-1), get2(1, mid-1)};
pii suf = {get1(mid+1, n), get2(mid+1, n)};
for(int i=1; i<=mid; i++){
int cur1 = add1(mul1(get1(1, i-1), bp1[mid-i]), get1(i+1, mid));
int cur2 = add2(mul2(get2(1, i-1), bp2[mid-i]), get2(i+1, mid));
pii cur = {cur1, cur2};
if(cur == suf){
flag = 0;
if(p.fi < 0) p = cur;
if(p != cur) isUnique = 0;
}
}
for(int i=mid+1; i<=n; i++){
int cur1 = add1(mul1(get1(mid, i-1), bp1[n-i]), get1(i+1, n));
int cur2 = add2(mul2(get2(mid, i-1), bp2[n-i]), get2(i+1, n));
pii cur = {cur1, cur2};
if(cur == pre){
flag = 1;
if(p.fi < 0) p = cur;
if(p != cur) isUnique = 0;
}
}
if(flag == -1) cout << "NOT POSSIBLE", exit(0);
if(!isUnique) cout << "NOT UNIQUE", exit(0);
if(!flag) for(int i=mid+1; i<=n; i++) cout << s[i];
else for(int i=1; i<mid; i++) cout << s[i];
}
int32_t main(){
fastIO;
//file(TASK);
nhap();
solve();
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2392 KB |
Output is correct |
2 |
Correct |
1 ms |
2648 KB |
Output is correct |
3 |
Correct |
1 ms |
2396 KB |
Output is correct |
4 |
Correct |
1 ms |
2396 KB |
Output is correct |
5 |
Correct |
1 ms |
2396 KB |
Output is correct |
6 |
Correct |
0 ms |
2396 KB |
Output is correct |
7 |
Correct |
1 ms |
2396 KB |
Output is correct |
8 |
Correct |
1 ms |
2396 KB |
Output is correct |
9 |
Correct |
0 ms |
2396 KB |
Output is correct |
10 |
Correct |
1 ms |
2392 KB |
Output is correct |
11 |
Correct |
1 ms |
2396 KB |
Output is correct |
12 |
Correct |
1 ms |
2396 KB |
Output is correct |
13 |
Correct |
1 ms |
2392 KB |
Output is correct |
14 |
Correct |
1 ms |
2396 KB |
Output is correct |
15 |
Correct |
1 ms |
2396 KB |
Output is correct |
16 |
Correct |
0 ms |
2396 KB |
Output is correct |
17 |
Correct |
0 ms |
2396 KB |
Output is correct |
18 |
Correct |
1 ms |
2396 KB |
Output is correct |
19 |
Correct |
1 ms |
2396 KB |
Output is correct |
20 |
Correct |
1 ms |
2396 KB |
Output is correct |
21 |
Correct |
1 ms |
2396 KB |
Output is correct |
22 |
Correct |
1 ms |
2396 KB |
Output is correct |
23 |
Correct |
1 ms |
2396 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 |
348 KB |
Output is correct |
27 |
Correct |
1 ms |
2396 KB |
Output is correct |
28 |
Correct |
1 ms |
2396 KB |
Output is correct |
29 |
Correct |
0 ms |
2396 KB |
Output is correct |
30 |
Correct |
1 ms |
2396 KB |
Output is correct |
31 |
Correct |
1 ms |
2396 KB |
Output is correct |
32 |
Correct |
1 ms |
2396 KB |
Output is correct |
33 |
Correct |
1 ms |
2396 KB |
Output is correct |
34 |
Correct |
0 ms |
2396 KB |
Output is correct |
35 |
Correct |
1 ms |
2396 KB |
Output is correct |
36 |
Correct |
1 ms |
2396 KB |
Output is correct |
37 |
Correct |
1 ms |
2396 KB |
Output is correct |
38 |
Correct |
1 ms |
2396 KB |
Output is correct |
39 |
Correct |
1 ms |
2392 KB |
Output is correct |
40 |
Correct |
1 ms |
2396 KB |
Output is correct |
41 |
Correct |
0 ms |
2396 KB |
Output is correct |
42 |
Correct |
1 ms |
2396 KB |
Output is correct |
43 |
Correct |
0 ms |
2396 KB |
Output is correct |
44 |
Correct |
1 ms |
2568 KB |
Output is correct |
45 |
Correct |
1 ms |
2396 KB |
Output is correct |
46 |
Correct |
1 ms |
2396 KB |
Output is correct |
47 |
Correct |
1 ms |
2396 KB |
Output is correct |
48 |
Correct |
1 ms |
2396 KB |
Output is correct |
49 |
Correct |
0 ms |
348 KB |
Output is correct |
50 |
Correct |
1 ms |
2396 KB |
Output is correct |
51 |
Correct |
1 ms |
2484 KB |
Output is correct |
52 |
Correct |
1 ms |
2396 KB |
Output is correct |
53 |
Correct |
1 ms |
2396 KB |
Output is correct |
54 |
Correct |
1 ms |
2396 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
103 ms |
65912 KB |
Output is correct |
2 |
Correct |
109 ms |
68020 KB |
Output is correct |
3 |
Correct |
105 ms |
67912 KB |
Output is correct |
4 |
Correct |
105 ms |
67912 KB |
Output is correct |
5 |
Correct |
115 ms |
67872 KB |
Output is correct |
6 |
Correct |
5 ms |
4344 KB |
Output is correct |
7 |
Correct |
84 ms |
67876 KB |
Output is correct |
8 |
Correct |
78 ms |
63756 KB |
Output is correct |
9 |
Correct |
98 ms |
64784 KB |
Output is correct |
10 |
Correct |
95 ms |
64736 KB |
Output is correct |
11 |
Correct |
68 ms |
61336 KB |
Output is correct |
12 |
Correct |
1 ms |
2396 KB |
Output is correct |
13 |
Correct |
0 ms |
2512 KB |
Output is correct |
14 |
Correct |
1 ms |
2396 KB |
Output is correct |
15 |
Correct |
1 ms |
2396 KB |
Output is correct |
16 |
Correct |
1 ms |
2512 KB |
Output is correct |
17 |
Correct |
1 ms |
2396 KB |
Output is correct |
18 |
Correct |
1 ms |
2396 KB |
Output is correct |
19 |
Correct |
1 ms |
2396 KB |
Output is correct |
20 |
Correct |
1 ms |
2396 KB |
Output is correct |
21 |
Correct |
1 ms |
2396 KB |
Output is correct |
22 |
Correct |
1 ms |
2396 KB |
Output is correct |
23 |
Correct |
1 ms |
2392 KB |
Output is correct |
24 |
Correct |
1 ms |
2396 KB |
Output is correct |
25 |
Correct |
0 ms |
2512 KB |
Output is correct |
26 |
Correct |
1 ms |
2396 KB |
Output is correct |
27 |
Correct |
1 ms |
2396 KB |
Output is correct |
28 |
Correct |
1 ms |
2396 KB |
Output is correct |
29 |
Correct |
1 ms |
2396 KB |
Output is correct |
30 |
Correct |
1 ms |
2396 KB |
Output is correct |
31 |
Correct |
1 ms |
2396 KB |
Output is correct |
32 |
Correct |
1 ms |
2396 KB |
Output is correct |
33 |
Correct |
1 ms |
2396 KB |
Output is correct |
34 |
Correct |
1 ms |
2396 KB |
Output is correct |
35 |
Correct |
0 ms |
456 KB |
Output is correct |
36 |
Correct |
0 ms |
348 KB |
Output is correct |
37 |
Correct |
0 ms |
348 KB |
Output is correct |
38 |
Correct |
1 ms |
2396 KB |
Output is correct |
39 |
Correct |
1 ms |
2396 KB |
Output is correct |
40 |
Correct |
1 ms |
2396 KB |
Output is correct |
41 |
Correct |
1 ms |
2396 KB |
Output is correct |
42 |
Correct |
1 ms |
2396 KB |
Output is correct |
43 |
Correct |
1 ms |
2396 KB |
Output is correct |
44 |
Correct |
1 ms |
2396 KB |
Output is correct |
45 |
Correct |
1 ms |
2396 KB |
Output is correct |
46 |
Correct |
0 ms |
2396 KB |
Output is correct |
47 |
Correct |
1 ms |
2516 KB |
Output is correct |
48 |
Correct |
1 ms |
2508 KB |
Output is correct |
49 |
Correct |
1 ms |
2396 KB |
Output is correct |
50 |
Correct |
1 ms |
2396 KB |
Output is correct |
51 |
Correct |
1 ms |
2396 KB |
Output is correct |
52 |
Correct |
1 ms |
2396 KB |
Output is correct |
53 |
Correct |
0 ms |
2396 KB |
Output is correct |
54 |
Correct |
1 ms |
2392 KB |
Output is correct |