#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " : " << x << '\n'
#define int ll
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef string str;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef pair<pll, pll> node;
typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
const ll Mod = 1000000009LL;
const int Maxn = 3e5 + 10;
const int Maxk = 60;
const ll Inf = 2242545357980376863LL;
const ll Log = 20;
const ll Base = 998244353;
int Rank[Log][Maxn], n;
int idx[Maxn];
ll ph[Maxn], phr[Maxn], pw[Maxn];
pii a[Maxn];
str s;
ll get(int l, int r){
return (ph[r] - (ph[l]*pw[r - l] % Mod) + Mod) % Mod;
}
ll get_rev(int l, int r){
return (phr[l] - (phr[r]*pw[r - l] % Mod) + Mod) % Mod;
}
int pal_range(int l, int r){
int L = 0, R = min(n - r, l) + 1, mid;
//int res = 0;
//for(int i = 0; i < R - 1; i ++) if(s[l - 1 - i] != s[r + i]) return i;
//return R - 1;
while(L + 1 < R){
mid = (L + R) >> 1;
if(get(l - mid, l) == get_rev(r, r + mid)) L = mid;
else R = mid;
}
return L;
}
int pal[Maxn];
int eq_range(int l1, int l2){
int L = 0, R = min(n - l1, n - l2) + 1, mid;
//for(int i = 0; i + 1 < R; i++) if(s[i + l1] != s[i + l2]) return i;
//return R - 1;
while(L + 1 < R){
mid = (L + R) >> 1;
if(get(l1, l1 + mid) == get(l2, l2 + mid)) L = mid;
else R = mid;
}
return L;
}
int eq[Maxn];
int f[Maxn], f2[Maxn];
vector<int> V;
stack<int> sta;
ll solve(){
while(!sta.empty()) sta.pop();
ll N = V.size();
//cerr << "N : " << N << '\n';
sta.push(0);
for(int i = 1; i < N-1; i++){
//cerr << i << " " << V[i] << '\n';
while(V[sta.top()] > V[i]) sta.pop();
f[i] = sta.top();
sta.push(i);
}
//cerr << "S" << '\n';
while(!sta.empty()) sta.pop();
sta.push(N-1);
for(int i = N-2; i > 0; i--){
while(V[sta.top()] >= V[i]) sta.pop();
f2[i] = sta.top();
sta.push(i);
}
ll res = 0;
for(int i = 1; i < N - 1; i++)
res = max(res, 1LL * (f2[i] - f[i]) * V[i]);
return res;
}
int32_t main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
pw[0] = 1;
for(int i = 1; i < Maxn; i++) pw[i] = (pw[i - 1] * Base) % Mod;
cin >> s;
n = s.size();
ph[0] = 0;
for(int i = 1; i <= n; i++) ph[i] = (ph[i - 1] * Base + s[i - 1]) % Mod;
phr[n] = 0;
for(int i = n - 1; i >= 0; i--) phr[i] = (phr[i + 1] * Base + s[i]) % Mod;
//cerr << get(0, 2) << " " << get(n-2, n) << '\n';
for(int i = 0; i < n; i++) Rank[0][i] = s[i];
int st;
for(int l = 1; l < Log; l++){
st = (1 << (l - 1));
for(int i = 0; i < n; i++){
a[i].F = Rank[l - 1][i];
a[i].S = (i + st < n ? Rank[l - 1][i + st] : -1);
}
sort(a, a + n);
for(int i = 0; i < n; i++)
Rank[l][i] = lower_bound(a, a + n, pii(Rank[l - 1][i], (i + st < n ? Rank[l - 1][i + st] : -1) )) - a;
}
for(int i = 0; i < n; i++) idx[Rank[Log - 1][i]] = i;
//cerr << '\n';
//for(int i = 0; i < n; i++) cerr << s.substr(idx[i], n) << '\n';
for(int i = 0; i < n - 1; i++) eq[i] = eq_range(idx[i], idx[i + 1]);
//for(int i = 0; i < n - 1; i++) cerr << eq[i] << ' ';
//cerr << '\n';
ll ans = 0;
for(int i = 0; i < n; i++) pal[i] = pal_range(i + 1, i);
//for(int i = 0; i < n; i++) cerr << pal[i] << ' ';
//cerr << '\n';
for(int x = 1; x <= n/2; x++){
ll cnt = (pal[idx[0]] >= x);
for(int i = 1; i < n; i++){
if(eq[i - 1] < x) cnt = 0;
cnt += (pal[idx[i]] >= x);
ans = max(ans, cnt * (x + x - 1));
}
}
/*
V.pb(-2);
for(int i = 0; i < n - 1; i++) V.pb( 2 * min(eq[i], min(pal[idx[i]], pal[idx[i + 1]])) - 1 );
V.pb(-2);
//for(auto x : V) cerr << x << ' '; cerr << '\n';
ans = max(ans, 2LL * (*max_element(pal, pal + n)) - 1);
ans = max(ans, solve());
*/
for(int i = 0; i < n; i++) pal[i] = pal_range(i, i);
//for(int i = 0; i < n; i++) cerr << pal[i] << ' ';
//cerr << '\n';
/*
V.clear();
V.pb(-2);
for(int i = 0; i < n - 1; i++) V.pb( 2 * min(eq[i], min(pal[idx[i]], pal[idx[i + 1]])) );
V.pb(-2);
//for(auto x : V) cerr << x << ' '; cerr << '\n';
ans = max(ans, 2LL * (*max_element(pal, pal + n)));
ans = max(ans, solve());
*/
for(int x = 1; x <= n/2; x++){
ll cnt = (pal[idx[0]] >= x);
for(int i = 1; i < n; i++){
if(eq[i - 1] < x) cnt = 0;
cnt += (pal[idx[i]] >= x);
ans = max(ans, cnt * (x + x));
}
}
cout << ans;
return 0;
}
/*
abacaba
*/
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
6 ms |
2936 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
10 ms |
3192 KB |
Output is correct |
| 2 |
Correct |
10 ms |
3136 KB |
Output is correct |
| 3 |
Correct |
9 ms |
3064 KB |
Output is correct |
| 4 |
Correct |
10 ms |
3064 KB |
Output is correct |
| 5 |
Correct |
9 ms |
3064 KB |
Output is correct |
| 6 |
Correct |
9 ms |
3056 KB |
Output is correct |
| 7 |
Correct |
11 ms |
3064 KB |
Output is correct |
| 8 |
Correct |
10 ms |
3068 KB |
Output is correct |
| 9 |
Correct |
11 ms |
3192 KB |
Output is correct |
| 10 |
Correct |
12 ms |
3064 KB |
Output is correct |
| 11 |
Correct |
11 ms |
3156 KB |
Output is correct |
| 12 |
Correct |
11 ms |
3064 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
223 ms |
5092 KB |
Output is correct |
| 2 |
Correct |
223 ms |
5112 KB |
Output is correct |
| 3 |
Correct |
216 ms |
4988 KB |
Output is correct |
| 4 |
Correct |
505 ms |
4984 KB |
Output is correct |
| 5 |
Correct |
281 ms |
5140 KB |
Output is correct |
| 6 |
Correct |
325 ms |
4984 KB |
Output is correct |
| 7 |
Correct |
223 ms |
4984 KB |
Output is correct |
| 8 |
Correct |
277 ms |
5092 KB |
Output is correct |
| 9 |
Correct |
295 ms |
4984 KB |
Output is correct |
| 10 |
Correct |
293 ms |
5112 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
1071 ms |
24312 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
1075 ms |
66772 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
