This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#pragma GCC optimize("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
using namespace std;
void Z(const string& s, vector<int>& z) {
z.assign(s.size(), 0);
int n = s.size();
int x = 0, y = 0;
for (int i = 1; i < n; i++) {
z[i] = max(0, min(z[i-x], y-i+1));
while (i+z[i] < n && s[z[i]] == s[i+z[i]]) {
x = i; y = i+z[i]; z[i]++;
}
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
//freopen("palindrome.in", "r", stdin);
//freopen("palindrome.out", "w", stdout);
string s;
cin >> s;
int n = s.length();
vector<int> z, cnt(n + 1, 0);
vector<bool> pal(n + 1, false);
long long res = 0;
for (int i = 0; i < n; i++) {
string t = s.substr(i, n - i);
string rt = t;
reverse(rt.begin(), rt.end());
string t2 = t;
t2 += '#';
t2 += rt;
Z(t2, z);
for (int j = 0; j <= n - i; j++) {
pal[j] = false;
cnt[j] = 0;
}
for (int j = 0; j < n - i; j++) {
if (z[z.size() - j - 1] == j + 1) {
pal[j] = 1;
}
}
t += '#';
t += s;
Z(t, z);
for (int j = n - i + 1; j < (int) z.size(); j++) {
cnt[z[j]]++;
}
for (int j = n - i - 1; j >= 0; j--) {
cnt[j] += cnt[j + 1];
}
for (int j = i; j < n; j++) {
if (pal[j - i]) {
int len = j - i + 1;
res = max(res, cnt[len] * 1LL * len);
}
}
}
cout << res << '\n';
return 0;
}
Compilation message (stderr)
In file included from /usr/include/x86_64-linux-gnu/c++/9/bits/gthr.h:148,
from /usr/include/c++/9/ext/atomicity.h:35,
from /usr/include/c++/9/bits/ios_base.h:39,
from /usr/include/c++/9/ios:42,
from /usr/include/c++/9/istream:38,
from /usr/include/c++/9/sstream:38,
from /usr/include/c++/9/complex:45,
from /usr/include/c++/9/ccomplex:39,
from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:54,
from palindrome.cpp:4:
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:102:1: error: option("tune=") was already specified
102 | __gthrw(pthread_once)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:102:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:103:1: error: option("tune=") was already specified
103 | __gthrw(pthread_getspecific)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:103:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:104:1: error: option("tune=") was already specified
104 | __gthrw(pthread_setspecific)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:104:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:106:1: error: option("tune=") was already specified
106 | __gthrw(pthread_create)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:106:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:107:1: error: option("tune=") was already specified
107 | __gthrw(pthread_join)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:107:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:108:1: error: option("tune=") was already specified
108 | __gthrw(pthread_equal)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:108:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:109:1: error: option("tune=") was already specified
109 | __gthrw(pthread_self)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:109:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:110:1: error: option("tune=") was already specified
110 | __gthrw(pthread_detach)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:110:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:112:1: error: option("tune=") was already specified
112 | __gthrw(pthread_cancel)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:112:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:114:1: error: option("tune=") was already specified
114 | __gthrw(sched_yield)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:114:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:116:1: error: option("tune=") was already specified
116 | __gthrw(pthread_mutex_lock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:116:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:117:1: error: option("tune=") was already specified
117 | __gthrw(pthread_mutex_trylock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:117:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:119:1: error: option("tune=") was already specified
119 | __gthrw(pthread_mutex_timedlock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:119:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:121:1: error: option("tune=") was already specified
121 | __gthrw(pthread_mutex_unlock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:121:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:122:1: error: option("tune=") was already specified
122 | __gthrw(pthread_mutex_init)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:122:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:123:1: error: option("tune=") was already specified
123 | __gthrw(pthread_mutex_destroy)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:123:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:125:1: error: option("tune=") was already specified
125 | __gthrw(pthread_cond_init)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:125:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:126:1: error: option("tune=") was already specified
126 | __gthrw(pthread_cond_broadcast)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:126:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:127:1: error: option("tune=") was already specified
127 | __gthrw(pthread_cond_signal)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:127:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:128:1: error: option("tune=") was already specified
128 | __gthrw(pthread_cond_wait)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:128:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:129:1: error: option("tune=") was already specified
129 | __gthrw(pthread_cond_timedwait)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:129:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:130:1: error: option("tune=") was already specified
130 | __gthrw(pthread_cond_destroy)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:130:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:132:1: error: option("tune=") was already specified
132 | __gthrw(pthread_key_create)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:132:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:133:1: error: option("tune=") was already specified
133 | __gthrw(pthread_key_delete)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:133:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:134:1: error: option("tune=") was already specified
134 | __gthrw(pthread_mutexattr_init)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:134:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:135:1: error: option("tune=") was already specified
135 | __gthrw(pthread_mutexattr_settype)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:135:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:136:1: error: option("tune=") was already specified
136 | __gthrw(pthread_mutexattr_destroy)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:136:1: error: option("tune=") was already specified
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:237:1: error: option("tune=") was already specified
237 | __gthrw2(__gthrw_(__pthread_key_create),
| ^~~~~~~~
/usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:237:1: error: option("tune=") was already specified
/usr/include/c++/9/shared_mutex:71:3: error: option("tune=") was already specified
71 | _GLIBCXX_GTHRW(rwlock_rdlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/9/shared_mutex:71:3: error: option("tune=") was already specified
/usr/include/c++/9/shared_mutex:72:3: error: option("tune=") was already specified
72 | _GLIBCXX_GTHRW(rwlock_tryrdlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/9/shared_mutex:72:3: error: option("tune=") was already specified
/usr/include/c++/9/shared_mutex:73:3: error: option("tune=") was already specified
73 | _GLIBCXX_GTHRW(rwlock_wrlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/9/shared_mutex:73:3: error: option("tune=") was already specified
/usr/include/c++/9/shared_mutex:74:3: error: option("tune=") was already specified
74 | _GLIBCXX_GTHRW(rwlock_trywrlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/9/shared_mutex:74:3: error: option("tune=") was already specified
/usr/include/c++/9/shared_mutex:75:3: error: option("tune=") was already specified
75 | _GLIBCXX_GTHRW(rwlock_unlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/9/shared_mutex:75:3: error: option("tune=") was already specified
/usr/include/c++/9/shared_mutex:89:4: error: option("tune=") was already specified
89 | __gthrw(pthread_rwlock_timedrdlock);
| ^~~~~~~
/usr/include/c++/9/shared_mutex:89:4: error: option("tune=") was already specified
/usr/include/c++/9/shared_mutex:99:4: error: option("tune=") was already specified
99 | __gthrw(pthread_rwlock_timedwrlock);
| ^~~~~~~
/usr/include/c++/9/shared_mutex:99:4: error: option("tune=") was already specified