#include <bits/stdc++.h>
#define nl '\n'
#ifdef LOCAL
#include "template/debug.hpp"
#else
#define dbg(...) ;
#define timer(...) ;
#endif
int random_base(int lb, int rb) {
bool deterministic = false;
assert(rb - lb >= 2);
int64_t seed = deterministic ? 1 : std::chrono::high_resolution_clock::now().time_since_epoch().count();
std::mt19937_64 rng(seed);
auto uid = std::uniform_int_distribution<long long>(lb + 1, rb - 1);
int base = uid(rng);
return base - (base % 2 == 0);
}
using HashType = std::pair<int, uint64_t>;
constexpr int h_mod = 1e9 + 123;
const int h_max_value = 1024;
int h_base = random_base(h_max_value, h_mod - 1);
std::vector<HashType> h_power = {{1, 1}};
void generate_power(int size) {
while ((int)h_power.size() < size) {
h_power.emplace_back((int64_t)h_power.back().first * h_base % h_mod,
h_power.back().second * h_base);
}
}
struct PolynomialHash {
std::vector<HashType> hval;
PolynomialHash() {}
// Assuming that s[i] > 0
PolynomialHash(const std::string& s) : hval(s.size() + 1) {
generate_power(s.size() + 1);
for (int i = 0; i < (int) s.size(); i++) {
hval[i + 1].first = ((int64_t) hval[i].first * h_base + s[i]) % h_mod;
hval[i + 1].second = hval[i].second * h_base + s[i];
}
}
// Assuming that s[i] > 0
PolynomialHash(const std::vector<int>& s) : hval(s.size() + 1) {
generate_power(s.size() + 1);
for (int i = 0; i < (int) s.size(); i++) {
hval[i + 1].first = ((int64_t) hval[i].first * h_base + s[i]) % h_mod;
hval[i + 1].second = hval[i].second * h_base + s[i];
}
}
// Get hash of range [l, r)
HashType get(int l, int r) {
int r1 = ((int64_t)hval[r].first -
(int64_t)hval[l].first * h_power[r - l].first) %
h_mod;
uint64_t r2 = hval[r].second - hval[l].second * h_power[r - l].second;
return {r1 + (r1 < 0) * h_mod, r2};
}
};
struct ReversePolynomialHash {
std::vector<HashType> hval;
ReversePolynomialHash() {}
// Assuming that s[i] > 0
ReversePolynomialHash(const std::string& s) : hval(s.size() + 1) {
generate_power(s.size() + 1);
for (int i = 0; i < (int) s.size(); i++) {
int j = s.size() - i - 1;
hval[i + 1].first = ((int64_t) hval[i].first * h_base + s[j]) % h_mod;
hval[i + 1].second = hval[i].second * h_base + s[j];
}
}
// Assuming that s[i] > 0
ReversePolynomialHash(const std::vector<int>& s) : hval(s.size() + 1) {
generate_power(s.size() + 1);
for (int i = 0; i < (int) s.size(); i++) {
int j = s.size() - i - 1;
hval[i + 1].first = ((int64_t) hval[i].first * h_base + s[j]) % h_mod;
hval[i + 1].second = hval[i].second * h_base + s[j];
}
}
// Get reverse hash of range [l, r)
HashType get(int l, int r) {
l = hval.size() - l - 1;
r = hval.size() - r - 1;
std::swap(l, r);
int r1 = ((int64_t)hval[r].first -
(int64_t)hval[l].first * h_power[r - l].first) %
h_mod;
uint64_t r2 = hval[r].second - hval[l].second * h_power[r - l].second;
return {r1 + (r1 < 0) * h_mod, r2};
}
};
const int mxN = 3e5 + 1;
std::map<HashType, int> mp[mxN];
signed main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
std::string s;
std::cin >> s;
int n = s.size();
PolynomialHash h1(s);
ReversePolynomialHash h1r(s);
for (int i = 0; i < n; i++) {
for (int j = i; j < n; j++) {
auto hf = h1.get(i, j + 1);
auto hr = h1r.get(i, j + 1);
if (hf == hr) {
mp[j - i + 1][hf]++;
}
}
}
int64_t ans = 0;
for (int len = 1; len <= n; len++) {
for (auto [hv, cnt] : mp[len]) {
ans = std::max(ans, (int64_t) cnt * len);
}
}
std::cout << ans << nl;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
14428 KB |
Output is correct |
2 |
Correct |
4 ms |
14556 KB |
Output is correct |
3 |
Correct |
4 ms |
14424 KB |
Output is correct |
4 |
Correct |
4 ms |
14428 KB |
Output is correct |
5 |
Correct |
4 ms |
14436 KB |
Output is correct |
6 |
Correct |
5 ms |
14428 KB |
Output is correct |
7 |
Correct |
4 ms |
14428 KB |
Output is correct |
8 |
Correct |
3 ms |
14428 KB |
Output is correct |
9 |
Correct |
4 ms |
14428 KB |
Output is correct |
10 |
Correct |
3 ms |
14424 KB |
Output is correct |
11 |
Correct |
3 ms |
14428 KB |
Output is correct |
12 |
Correct |
3 ms |
14356 KB |
Output is correct |
13 |
Correct |
4 ms |
14428 KB |
Output is correct |
14 |
Correct |
3 ms |
14424 KB |
Output is correct |
15 |
Correct |
4 ms |
14424 KB |
Output is correct |
16 |
Correct |
3 ms |
14424 KB |
Output is correct |
17 |
Correct |
4 ms |
14428 KB |
Output is correct |
18 |
Correct |
4 ms |
14428 KB |
Output is correct |
19 |
Correct |
4 ms |
14424 KB |
Output is correct |
20 |
Correct |
4 ms |
14428 KB |
Output is correct |
21 |
Correct |
4 ms |
14548 KB |
Output is correct |
22 |
Correct |
3 ms |
14428 KB |
Output is correct |
23 |
Correct |
4 ms |
14428 KB |
Output is correct |
24 |
Correct |
4 ms |
14456 KB |
Output is correct |
25 |
Correct |
5 ms |
14428 KB |
Output is correct |
26 |
Correct |
4 ms |
14428 KB |
Output is correct |
27 |
Correct |
4 ms |
14428 KB |
Output is correct |
28 |
Correct |
4 ms |
14428 KB |
Output is correct |
29 |
Correct |
4 ms |
14460 KB |
Output is correct |
30 |
Correct |
4 ms |
14428 KB |
Output is correct |
31 |
Correct |
3 ms |
14424 KB |
Output is correct |
32 |
Correct |
3 ms |
14544 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
10 ms |
14428 KB |
Output is correct |
2 |
Correct |
8 ms |
14428 KB |
Output is correct |
3 |
Correct |
9 ms |
14428 KB |
Output is correct |
4 |
Correct |
7 ms |
14548 KB |
Output is correct |
5 |
Correct |
8 ms |
14428 KB |
Output is correct |
6 |
Correct |
8 ms |
14428 KB |
Output is correct |
7 |
Correct |
8 ms |
14432 KB |
Output is correct |
8 |
Correct |
10 ms |
14424 KB |
Output is correct |
9 |
Correct |
8 ms |
14424 KB |
Output is correct |
10 |
Correct |
7 ms |
14448 KB |
Output is correct |
11 |
Correct |
8 ms |
14436 KB |
Output is correct |
12 |
Correct |
8 ms |
14424 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
555 ms |
15676 KB |
Output is correct |
2 |
Correct |
478 ms |
15432 KB |
Output is correct |
3 |
Correct |
511 ms |
15664 KB |
Output is correct |
4 |
Correct |
505 ms |
15584 KB |
Output is correct |
5 |
Correct |
368 ms |
15496 KB |
Output is correct |
6 |
Correct |
368 ms |
15448 KB |
Output is correct |
7 |
Correct |
411 ms |
15520 KB |
Output is correct |
8 |
Correct |
381 ms |
15176 KB |
Output is correct |
9 |
Correct |
362 ms |
15176 KB |
Output is correct |
10 |
Correct |
380 ms |
15448 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1031 ms |
25488 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1044 ms |
48880 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |