Submission #792128

#	Time	Username	Problem	Language	Result	Execution time	Memory
792128		cig32	Cat Exercise (JOI23_ho_t4)	C++17	74 / 100	2062 ms	479268 KiB

Main

#include "bits/stdc++.h"
using namespace std;
#define int long long
const int MAXN = 2e5 + 10;
const int MOD = 1e9 + 7;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
  int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
int bm(int b, int p) {
  if(p==0) return 1 % MOD;
  int r = bm(b, p >> 1);
  if(p&1) return (((r*r) % MOD) * b) % MOD;
  return (r*r) % MOD;
}
int inv(int b) { 
  return bm(b, MOD-2);
}
int fastlog(int x) {
  return (x == 0 ? -1 : 64 - __builtin_clzll(x) - 1);
}
void printcase(int i) { cout << "Case #" << i << ": "; }
set<int>adj[MAXN];
set<int>nums[MAXN];
int dsu[MAXN];
int n, p[MAXN];
int pos[MAXN];
bool vis[MAXN];
int nxtset;
vector<int> euler;
int l[MAXN], r[MAXN], dep[MAXN];
void dfs0(int node, int prv) {
  euler.push_back(node);
  dep[node] = (prv == -1 ? 0 : dep[prv] + 1);
  for(int x: adj[node]) {
    if(x != prv) {
      dfs0(x, node);
      euler.push_back(node);
    }
  }
}
int st[19][2*MAXN];
int lcadep(int x, int y) {
  int m1 = min(l[x], l[y]);
  int m2 = max(r[x], r[y]);
  int k = 32 - __builtin_clz(m2-m1+1) - 1;
  return min(st[k][m1], st[k][m2-(1<<k)+1]);
}
int dist(int x, int y) {
  return dep[x] + dep[y] - 2 * lcadep(x, y);
}
int recur(int node) {
  if(adj[node].empty()) return 0;
  int cat = dsu[node];
  int boss = *nums[cat].rbegin();
  nums[cat].erase(boss);
  node = pos[boss];
  vector<int> visited; // Remember to turn all of them to not visited at the end
  vis[node] = 1;
  visited.push_back(node);
  vector<int> start;
  start.push_back(0);
  for(int x: adj[node]) start.push_back(x);
  int len = start.size() - 1;
  int nxt[len+1],  prv[len+1];
  queue<int> q[len+1];
  for(int i=1; i<=len; i++) {
    nxt[i] = i+1;
    prv[i] = i-1;
    q[i].push(start[i]);
  }
  nxt[0] = 1;
  vector<int> bruh[len+1]; // respective lists
  vector<int>ranks; // rank according ascending of size
  while(1) {
    int id=0;
    while(nxt[id]!=len+1){
      if(ranks.size() + 1 == len) break;
      id=nxt[id];
      int f = q[id].front();
      q[id].pop();
      vis[f]=1;
      bruh[id].push_back(f);
      visited.push_back(f);
      for(int x:adj[f]) {
        if(!vis[x]) {
          q[id].push(x);
        }
      }
      if(q[id].empty()) {
        for(int x:bruh[id]){
          dsu[x]=nxtset;
          nums[cat].erase(p[x]);
          nums[nxtset].insert(p[x]);
        }
        ranks.push_back(id);
        nxtset++;
        nxt[prv[id]]=nxt[id];
        prv[nxt[id]]=prv[id];
      }
    }
    if(ranks.size() + 1 == len) break;
  }
  for(int x:visited)vis[x]=0;
  vector<pair<int,int>>vt;
  for(int i=1; i<=len; i++) {
    vt.push_back({*nums[dsu[start[i]]].rbegin(),pos[*nums[dsu[start[i]]].rbegin()]});
  }
  for(int x: adj[node]) {
    adj[x].erase(node);
  }
  int res = 0;
  for(pair<int, int> x: vt) {
    res = max(res, dist(node, x.second) + recur(x.second));
  }
  return res;
}
void solve(int tc) {
  cin >> n;
  for(int i=1; i<=n; i++) cin >> p[i];
  for(int i=1; i<=n; i++) pos[p[i]] = i;
  for(int i=1; i<n; i++) {
    int a, b;
    cin >> a >> b;
    adj[a].insert(b);
    adj[b].insert(a);
  }
  dfs0(1, -1);
  for(int i=0; i<euler.size(); i++) r[euler[i]] = i;
  for(int i=euler.size()-1; i>=0; i--) l[euler[i]] = i;
  for(int i=0; i<euler.size(); i++) st[0][i] = dep[euler[i]];
  for(int i=1; i<19; i++) {
    for(int j=0; j+(1<<i)-1<euler.size(); j++) {
      st[i][j] = min(st[i-1][j], st[i-1][j+(1<<(i-1))]);
    }
  }
  for(int i=1; i<=n; i++) dsu[i]=1;
  for(int i=1; i<=n; i++) nums[1].insert(i);
  nxtset=2;
  cout<<recur(1)<<'\n';

}
int32_t main() {
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
}
// 勿忘初衷

Compilation message (stderr)

Main.cpp: In function 'long long int recur(long long int)':
Main.cpp:78:27: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   78 |       if(ranks.size() + 1 == len) break;
      |          ~~~~~~~~~~~~~~~~~^~~~~~
Main.cpp:102:25: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
  102 |     if(ranks.size() + 1 == len) break;
      |        ~~~~~~~~~~~~~~~~~^~~~~~
Main.cpp: In function 'void solve(long long int)':
Main.cpp:129:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  129 |   for(int i=0; i<euler.size(); i++) r[euler[i]] = i;
      |                ~^~~~~~~~~~~~~
Main.cpp:131:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  131 |   for(int i=0; i<euler.size(); i++) st[0][i] = dep[euler[i]];
      |                ~^~~~~~~~~~~~~
Main.cpp:133:28: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  133 |     for(int j=0; j+(1<<i)-1<euler.size(); j++) {
      |                  ~~~~~~~~~~^~~~~~~~~~~~~

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