Submission #1028798

#	Time	Username	Problem	Language	Result	Execution time	Memory
1028798		NeroZein	Cat Exercise (JOI23_ho_t4)	C++17	31 / 100	2087 ms	43432 KiB

Main

#include "bits/stdc++.h"
using namespace std;

#ifdef Nero
#include "Deb.h"
#else
#define debug(...)
#endif

const int N = 2e5 + 5; 

int a[N];
int dep[N];
vector<int> g[N];
vector<pair<int, int>> t[N];

int dfs(int root, int v, int p) {
  if (a[v] > a[root]) {
    return 0;
  }
  int ret = v; 
  for (int u : g[v]) {
    if (u == p) {
      continue; 
    }
    dep[u] = dep[v] + 1; 
    int ret2 = dfs(root, u, v);
    if (a[ret2] > a[ret]) {
      ret = ret2;
    }
    if (v == root) {
      t[v].push_back({ret2, dep[ret2]}); 
    }
  }
  return ret; 
}

long long dfs2(int v) {
  long long ret = 0; 
  for (auto [u, w] : t[v]) {
    long long ret2 = dfs2(u);
    ret = max(ret, ret2 + w);
  }
  return ret; 
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n;
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
  }
  for(int i = 0; i < n - 1; ++i) {
    int u, v;
    cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  int root = 1; 
  for (int i = 1; i <= n; ++i) {
    if (a[i] == n) {
      root = i; 
    }
  }
  for (int i = 1; i <= n; ++i) {
    dep[i] = 0; 
    dfs(i, i, i);
  }
  cout << dfs2(root); 
  return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 7 / 7
• Subtask 4: 10 / 10
• Subtask 5: 0 / 20
• Subtask 6: 0 / 23
• Subtask 7: 0 / 26