Submission #1144015

#	Time	Username	Problem	Language	Result	Execution time	Memory
1144015		fryingduc	Synchronization (JOI13_synchronization)	C++20	100 / 100	182 ms	26284 KiB

synchronization

// https://github.com/dolphingarlic/CompetitiveProgramming/blob/master/JOI/JOI%2013-synchronisation.cpp
#include "bits/stdc++.h"
using namespace std;

#ifdef duc_debug
#include "bits/debug.h"
#else
#define debug(...)
#endif

const int maxn = 2e5 + 5;
const int LG = 19;
int n, m, q;
vector<int> g[maxn];
int eu[maxn], ev[maxn];
int tin[maxn], tout[maxn], timer;
int stt[maxn], lst[maxn];
int up[maxn][LG + 1], h[maxn];
bool active[maxn];

int bit[maxn];
void update(int i, int val) {
  for(; i <= timer; i += i & (-i)) {
    bit[i] += val;
  }
}

int get(int i) {
  int ans = 0;
  for(; i > 0; i -= i & (-i)) {
    ans += bit[i];
  }
  return ans;
}

void pre_dfs(int u, int prev) {
  tin[u] = ++timer;
  stt[u] = 1;
  for(auto v:g[u]) {
    if(v == prev) continue;
    h[v] = h[u] + 1;
    up[v][0] = u;
    for(int i = 1; i <= LG; ++i) {
      up[v][i] = up[up[v][i - 1]][i - 1];
    }
    pre_dfs(v, u);
  }
  tout[u] = ++timer;
}

void upd(int u, int d) {
  update(tin[u], d);
  update(tout[u], -d);
}

int find(int u) {
  for(int i = LG; i >= 0; --i) {
    if(up[u][i] and get(tin[up[u][i]]) == get(tin[u])) {
      u = up[u][i];
    }
  }
  return u;
}

void solve() {
  cin >> n >> m >> q;
  for(int i = 1; i < n; ++i) {
    int u, v; cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u);
    eu[i] = u, ev[i] = v;
  }
  pre_dfs(1, 0);
  for(int i = 1; i <= n; ++i) {
    upd(i, -1);
  }
  while(m--) {
    int e; cin >> e;
    int u = eu[e], v = ev[e];
    if(h[u] > h[v]) swap(u, v);
    if(!active[e]) {
      stt[find(u)] += stt[v] - lst[v];
      upd(v, 1);
    } else {
      stt[v] = lst[v] = stt[find(u)];
      upd(v, -1);
    }
    active[e] ^= 1;
  }
  while(q--) {
    int u; cin >> u;
    cout << stt[find(u)] << '\n';
  }
}

signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  solve();

  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 10 / 10
• Subtask 4: 20 / 20
• Subtask 5: 40 / 40