| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 637444 |
2022-09-01T19:15:38 Z |
vovamr |
Lampice (COCI19_lampice) |
C++17 |
|
5000 ms |
9388 KB |
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define fi first
#define se second
#define ll long long
#define ld long double
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define mpp make_pair
#define ve vector
using namespace std;
using namespace __gnu_pbds;
template<class T> using oset = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
const ll inf = 1e18; const int iinf = 1e9;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T> inline bool chmin(T& a, T b) { return (a > b ? a = b, 1 : 0); }
template <typename T> inline bool chmax(T& a, T b) { return (a < b ? a = b, 1 : 0); }
constexpr int md = 1e9 + 9; constexpr int iv2 = (md + 1) / 2;
inline int add(int a, int b) { a += b; if(a>=md){a-=md;} return a; }
inline int sub(int a, int b) { a -= b; if(a<0){a+=md;} return a; }
inline int mul(int a, int b) { return (ll)a * b % md; }
inline int bp(int a, int n) { int res = 1;
for (; n; n >>= 1, a = mul(a, a)) {
if (n & 1) res = mul(res, a);
} return res;
}
inline int inv(int a) { return bp(a, md - 2); }
constexpr int p = 10039;
const int N = 5e4 + 100;
int pw[N];
inline void calc() {
pw[0] = 1;
for (int i = 1; i < N; ++i) pw[i] = mul(pw[i - 1], p);
}
int a[N];
ve<int> gr[N];
int used[N], sz[N];
inline void dfs1(int v, int p) {
sz[v] = 1;
for (auto &to : gr[v]) if (to != p && !used[to]) {
dfs1(to, v);
sz[v] += sz[to];
}
}
inline int centr(int v, int p, int n) {
for (auto &to : gr[v]) if (to != p && !used[to] && sz[to] > n / 2) {
return centr(to, v, n);
} return v;
}
int u[N], d[N];
inline void hashes(int v, int p, int h) {
if (v == p) u[v] = d[v] = a[v];
// cout << v + 1 << " " << a[v] << " " << u[v] << " " << d[v] << '\n';
for (auto &to : gr[v]) if (to != p && !used[to]) {
u[to] = add(u[v], mul(pw[h + 1], a[to]));
d[to] = add(a[to], mul(pw[1], d[v]));
hashes(to, v, h + 1);
}
}
bool found = 0;
map<int,int> mp;
ve<int> cur_path;
inline void dfs(int v, int p, const int &l) {
cur_path.pb(v);
if (sz(cur_path) == l && u[v] == d[v]) {
found = 1;
// cout << "hui " << v + 1 << '\n';
}
int x = l + 1 - sz(cur_path); // other length
int id = sz(cur_path) - x;
if (id >= 0 && id < sz(cur_path) && sz(cur_path) >= x) {
int node = cur_path[id];
if (u[node] == d[node]) {
int P = !id ? 0 : d[cur_path[id - 1]];
int H = sub(d[v], mul( P, pw[x] ));
if (mp.count(H)) {
// cout << "hui1 " << v + 1 << " " << sz(cur_path) << " " << x << '\n';
found = 1;
}
}
}
for (auto &to : gr[v]) {
if (to == p || used[to]) continue;
dfs(to, v, l);
}
cur_path.pop_back();
}
inline void add(int v, int p, const int &delta) {
mp[d[v]] += delta; if (!mp[d[v]]) mp.erase(d[v]);
for (auto &to : gr[v]) if (to != p && !used[to]) {
add(to, v, delta);
}
}
inline void cd(int v, int p, const int &l) {
used[v] = 1;
// cout << "centroid " << v + 1 << ":" << '\n';
dfs1(v, v);
hashes(v, v, 0);
mp.clear();
for (auto &to : gr[v]) {
if (to == p || used[to]) continue;
add(to, v, +1);
}
cur_path = {v};
for (auto &to : gr[v]) {
if (to == p || used[to]) continue;
add(to, v, -1);
dfs(to, v, l);
add(to, v, +1);
}
for (auto &to : gr[v]) {
if (to == p || used[to]) continue;
int c = centr(to, v, sz[to]);
cd(c, v, l);
}
}
inline void solve() { calc();
int n;
cin >> n;
for (int i = 0; i < n; ++i) {
char x;
cin >> x;
a[i] = x - 'a' + 1;
}
for (int i = 1; i < n; ++i) {
int v, u;
cin >> v >> u, --v, --u;
gr[v].pb(u), gr[u].pb(v);
}
int answer = 0;
int l, r, m, ans;
// cd(0, 0, 3);
// cout << '\n' << '\n';
// return;
// even
l = 1, r = n / 2, ans = 0;
while (l <= r) {
m = l + r >> 1;
found = 0;
fill(used, used + n, 0);
cd(0, 0, 2 * m);
if (found) ans = m, l = m + 1;
else r = m - 1;
} chmax(answer, 2 * ans);
// odd
l = 1, r = (n - 1) / 2, ans = 0;
while (l <= r) {
m = l + r >> 1;
found = 0;
fill(used, used + n, 0);
cd(0, 0, 2 * m + 1);
if (found) ans = m, l = m + 1;
else r = m - 1;
} chmax(answer, 2 * ans + 1);
cout << answer;
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int q = 1; // cin >> q;
while (q--) solve();
cerr << fixed << setprecision(3) << "Time execution: " << (double)clock() / CLOCKS_PER_SEC << endl;
}
Compilation message
lampice.cpp: In function 'void solve()':
lampice.cpp:175:9: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
175 | m = l + r >> 1;
| ~~^~~
lampice.cpp:186:9: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
186 | m = l + r >> 1;
| ~~^~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
11 ms |
1620 KB |
Output is correct |
| 2 |
Correct |
35 ms |
1748 KB |
Output is correct |
| 3 |
Correct |
136 ms |
1876 KB |
Output is correct |
| 4 |
Correct |
166 ms |
1880 KB |
Output is correct |
| 5 |
Correct |
1 ms |
1620 KB |
Output is correct |
| 6 |
Correct |
2 ms |
1620 KB |
Output is correct |
| 7 |
Correct |
1 ms |
1620 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
5067 ms |
9388 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
5067 ms |
8032 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
11 ms |
1620 KB |
Output is correct |
| 2 |
Correct |
35 ms |
1748 KB |
Output is correct |
| 3 |
Correct |
136 ms |
1876 KB |
Output is correct |
| 4 |
Correct |
166 ms |
1880 KB |
Output is correct |
| 5 |
Correct |
1 ms |
1620 KB |
Output is correct |
| 6 |
Correct |
2 ms |
1620 KB |
Output is correct |
| 7 |
Correct |
1 ms |
1620 KB |
Output is correct |
| 8 |
Execution timed out |
5067 ms |
9388 KB |
Time limit exceeded |
| 9 |
Halted |
0 ms |
0 KB |
- |
