#include <bits/stdc++.h>
using namespace std;
using db = long double;
using ll = long long;
using pl = pair<ll, ll>;
using pi = pair<int, int>;
#define vt vector
#define f first
#define s second
#define pb push_back
#define all(x) x.begin(), x.end()
#define size(x) ((int) (x).size())
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define F0R(i, b) FOR (i, 0, b)
#define endl '\n'
const ll INF = 1e18;
const int inf = 1e9;
/*
if a < b and b < c, then a < c
use string hashing
*/
const int m = 27;
const ll mod = 1e9 + 7;
const ll mx = 2e6 + 1;
ll powm(ll y) {
ll x = m;
ll res = 1;
while (y) {
if (y & 1) res = (res * x) % mod;
y >>= 1;
x = (x * x) % mod;
}
return res;
}
int n;
vt<vt<int>> adj;
vt<int> dp;
map<int, int> seen;
void push_back(pl& hash, int c) {
hash = {(hash.f * m + c + 1) % mod, hash.s + 1};
}
void push_front(pl& hash, int c) {
hash = {(powm(hash.s) * (c + 1) + hash.f) % mod, hash.s + 1};
}
const pl hid = {0, 0};
int dfs(int u) {
if (dp[u] != -1) return dp[u];
int res = 0;
for (int v : adj[u]) {
res = max(res, dfs(v));
}
return dp[u] = res + 1;
}
main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n;
adj.resize(n);
dp.resize(n, -1);
seen.reserve(n);
F0R (i, n) {
pl lhs = hid, rhs = hid;
string st; cin >> st;
F0R (j, size(st)) {
push_back(lhs, st[j] - 'A');
push_front(rhs, st[size(st) - j - 1] - 'A');
if (lhs.f == rhs.f) {
auto it = seen.find(lhs.f);
if (it != seen.end()) {
adj[it->s].pb(i);
}
}
}
seen[lhs.f] = i;
}
F0R (i, n) dfs(i);
cout << *max_element(all(dp)) << endl;
}
Compilation message
savez.cpp:68:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
68 | main() {
| ^~~~
savez.cpp: In function 'int main()':
savez.cpp:74:10: error: 'class std::map<int, int>' has no member named 'reserve'
74 | seen.reserve(n);
| ^~~~~~~
