#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'
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 = 1e9 + 9;
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];
vector<int> Rdx[Maxn];
vector<int> Rdx2[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 par[Maxn], sz[Maxn];
vector<int> Merge[Maxn];
vector<int> On[Maxn];
int get_par(int u){
if(par[u] == u) return u;
return par[u] = get_par(par[u]);
}
void merge(int u, int v){
u = get_par(u); v = get_par(v);
sz[u] += sz[v];
par[v] = par[u];
}
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);
}
*/
for(int i = 0; i <= max(n + 1, 200); i++) Rdx[i].clear(), Rdx2[i].clear();
for(int i = 0; i < n; i++) Rdx[(i + st < n ? Rank[l - 1][i + st] : -1) + 1].pb(i);
for(int j = 0; j <= max(n + 1, 200); j++)
for(int i : Rdx[j])
Rdx2[Rank[l - 1][i]].pb(i);
int po = 0;
for(int j = 0; j <= max(n + 1, 200); j++)
for(int i : Rdx2[j])
Rank[l][i] = po ++;
/*
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;
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++) Merge[eq[i]].pb(i);
ll ans = 0;
for(int i = 0; i < n; i++) pal[i] = pal_range(i + 1, i);
for(int i = 0; i < n; i++) On[pal[i]].pb(Rank[Log - 1][i]);
iota(par, par + Maxn, 0);
fill(sz, sz + Maxn, 0);
int mx = 0;
for(int x = n + 1; x >= 1; x--){
for(auto y : Merge[x]){
merge(y, y + 1);
mx = max(mx, sz[get_par(y)]);
}
for(auto y : On[x]){
sz[get_par(y)] ++;
mx = max(mx, sz[get_par(y)]);
}
ans = max(ans, 1LL * mx * (x + x - 1));
}
for(int i = 0; i < n; i++) pal[i] = pal_range(i, i);
for(int i = 0; i < Maxn; i++) On[i].clear();
for(int i = 0; i < Maxn; i++) On[pal[i]].pb(Rank[Log - 1][i]);
iota(par, par + Maxn, 0);
fill(sz, sz + Maxn, 0);
mx = 0;
for(int x = n + 1; x >= 1; x--){
for(auto y : Merge[x]){
merge(y, y + 1);
mx = max(mx, sz[get_par(y)]);
}
for(auto y : On[x]){
sz[get_par(y)] ++;
mx = max(mx, sz[get_par(y)]);
}
ans = max(ans, 1LL * mx * (x + x));
}
cout << ans << '\n';;
return 0;
}
/*
abacaba
*/
Compilation message
/tmp/ccSeaNsj.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/cclEe6Wy.o:koala.cpp:(.text.startup+0x0): first defined here
/tmp/ccSeaNsj.o: In function `runGame(int)':
grader.cpp:(.text+0x137): undefined reference to `minValue(int, int)'
grader.cpp:(.text+0x16b): undefined reference to `allValues(int, int, int*)'
grader.cpp:(.text+0x1a7): undefined reference to `maxValue(int, int)'
grader.cpp:(.text+0x1d7): undefined reference to `greaterValue(int, int)'
collect2: error: ld returned 1 exit status
