#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 2e5 + 5;
const int MAX_L = __lg(MAX_N) + 1;
bitset<MAX_N> used_c, used_s;
unordered_map<int, int> pos[MAX_N];
set<pair<int, int>> values[MAX_N];
vector<int> graph[MAX_N], parent[MAX_N], dist[MAX_N];
vector<bool> deleted[MAX_N];
int ancestors[MAX_N][MAX_L], num[MAX_N] = {}, value[MAX_N], sz[MAX_N];
void find_sizes(int u, int p) {
sz[u] = 1;
for (int v : graph[u]) {
if (v != p && !used_c[v]) {
find_sizes(v, u);
sz[u] += sz[v];
}
}
}
int find_centroid(int u, int p, int n) {
for (int v : graph[u]) {
if (v != p && !used_c[v] && sz[v] > n / 2) {
return find_centroid(v, u, n);
}
}
return u;
}
void DFS(int u, int c, int p, int d, int& t) {
pos[c][u] = t;
dist[c].push_back(d);
parent[c].push_back(p);
deleted[c].push_back(false);
values[c].insert({value[u], u});
ancestors[u][num[u]++] = c;
for (int v : graph[u]) {
if (v != p && !used_c[v]) {
DFS(v, c, u, d + 1, ++t);
}
}
}
void centroid(int u) {
find_sizes(u, -1);
int t = 0;
DFS(u, u, -1, 0, t);
used_c[u] = true;
for (int v : graph[u]) {
if (!used_c[v]) {
centroid(find_centroid(v, u, sz[v]));
}
}
}
void delete_subtree(int u, int p, int c) {
values[c].erase({value[u], u});
deleted[c][u] = true;
for (int v : graph[u]) {
if (v != p && pos[c].count(v) && !deleted[c][v]) {
delete_subtree(v, u, c);
}
}
}
int64_t solve(int u) {
used_s[u] = true;
int64_t ans = 0;
for (int i = 0; i < num[u]; i++) {
int A = ancestors[u][i];
if (!deleted[A][pos[A][u]]) {
delete_subtree(u, parent[A][pos[A][u]], A);
}
}
for (int v : graph[u]) {
if (!used_s[v]) {
tuple<int, int, int> val = {-1, -1, -1};
for (int i = 0; i < num[v]; i++) {
int A = ancestors[v][i];
if (!deleted[A][pos[A][v]] && !values[A].empty()) {
auto [valx, x] = *values[A].rbegin();
val = max(val, {valx, -(dist[A][pos[A][x]] + dist[A][pos[A][v]]), x});
}
}
ans = max(ans, solve(get<2>(val)) - get<1>(val) + 1);
}
}
return ans;
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int N;
cin >> N;
for (int i = 0; i < N; i++) {
cin >> value[i];
}
for (int i = 0; i < N - 1; i++) {
int u, v;
cin >> u >> v;
u--, v--;
graph[u].push_back(v);
graph[v].push_back(u);
}
centroid(find_centroid(0, -1, N));
for (int i = 0; i < N; i++) {
if (value[i] == N) {
cout << solve(i) << "\n";
}
}
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
20 ms |
42592 KB |
Output is correct |
2 |
Runtime error |
1178 ms |
1048576 KB |
Execution killed with signal 9 |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
20 ms |
42592 KB |
Output is correct |
2 |
Runtime error |
1178 ms |
1048576 KB |
Execution killed with signal 9 |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
20 ms |
42592 KB |
Output is correct |
2 |
Runtime error |
1178 ms |
1048576 KB |
Execution killed with signal 9 |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
20 ms |
42592 KB |
Output is correct |
2 |
Runtime error |
1178 ms |
1048576 KB |
Execution killed with signal 9 |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
20 ms |
42592 KB |
Output is correct |
2 |
Runtime error |
1178 ms |
1048576 KB |
Execution killed with signal 9 |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
23 ms |
42552 KB |
Output is correct |
2 |
Runtime error |
1811 ms |
1048576 KB |
Execution killed with signal 9 |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
20 ms |
42592 KB |
Output is correct |
2 |
Runtime error |
1178 ms |
1048576 KB |
Execution killed with signal 9 |
3 |
Halted |
0 ms |
0 KB |
- |