#define taskname "" #include <bits/stdc++.h> using namespace std; const int kMaxN = 100005; const int kMaxLog = 18; int n, m, q, timer; int in[kMaxN], out[kMaxN], jump[kMaxLog][kMaxN]; int info_count[kMaxN], duplicate_count[kMaxN]; bool enabled[kMaxN]; vector<int> adj[kMaxN]; vector<pair<int, int>> edges; void DFS(int u, int p) { in[u] = ++timer; for (int v : adj[u]) { if (v == p) { continue; } jump[0][v] = u; for (int i = 1; i < kMaxLog; i++) { jump[i][v] = jump[i - 1][jump[i - 1][v]]; } DFS(v, u); } out[u] = timer; } struct FenwickTree { int n; vector<int> bit; FenwickTree() {} FenwickTree(int _n) : n(_n) { bit.resize(n + 1, 0); } void Update(int pos, int val) { for (int i = pos; i <= n; i += i & (-i)) { bit[i] += val; } } int PrefixSum(int pos) { int sum = 0; for (int i = pos; i > 0; i -= i & (-i)) { sum += bit[i]; } return sum; } } ft; int FindSet(int u) { for (int i = kMaxLog - 1; i >= 0; i--) { if (jump[i][u] >= 1 && ft.PrefixSum(in[jump[i][u]]) == ft.PrefixSum(in[u])) { u = jump[i][u]; } } return u; } int main() { if (fopen(taskname".inp", "r")) { freopen(taskname".inp", "r", stdin); freopen(taskname".out", "w", stdout); } ios_base::sync_with_stdio(false); cin.tie(nullptr); cin >> n >> m >> q; for (int i = 1; i < n; i++) { int x, y; cin >> x >> y; edges.push_back({x, y}); adj[x].push_back(y); adj[y].push_back(x); } int root = 1; DFS(root, -1); ft = FenwickTree(n); for (int i = 1; i <= n; i++) { info_count[i] = 1; if (i != root) { ft.Update(in[i], 1); ft.Update(out[i] + 1, -1); } } while (m--) { int d; cin >> d; d--; int u = edges[d].first, v = edges[d].second; if (jump[0][u] == v) { swap(u, v); } if (!enabled[d]) { info_count[FindSet(u)] += info_count[v] - duplicate_count[v]; ft.Update(in[v], -1); ft.Update(out[v] + 1, 1); } else { info_count[v] = info_count[FindSet(u)]; duplicate_count[v] = info_count[v]; ft.Update(in[v], 1); ft.Update(out[v] + 1, -1); } enabled[d] = !enabled[d]; } while (q--) { int c; cin >> c; cout << info_count[FindSet(c)] << '\n'; } return 0; }

synchronization.cpp: In function 'int main()':
synchronization.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen(taskname".inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen(taskname".out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~