usaco 866 gathering

#include <bits/stdc++.h>
#define ll long long
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pli pair<ll,int>
#define fi first
#define se second
#define inf (INT_MAX/2-1)
#define infl (1LL<<60)
#define vi vector<int>
#define pb push_back
#define sz(a) (int)(a).size()
#define all(a) begin(a),end(a)
#define y0 y5656
#define y1 y7878
#define aaa system("pause");
#define dbg(x) cerr<<(#x)<<": "<<(x)<<'\n',aaa
#define dbga(x,n) cerr<<(#x)<<"[]: ";for(int _=0;_<n;_++)cerr<<x[_]<<' ';cerr<<'\n',aaa
#define dbgs(x) cerr<<(#x)<<"[stl]: ";for(auto _:x)cerr<<_<<' ';cerr<<'\n',aaa
#define dbgp(x) cerr<<(#x)<<": "<<x.fi<<' '<<x.se<<'\n',aaa
#define maxn 100000
#define ml2 18

using namespace std;

ifstream fin ("gathering.in");
ofstream fout ("gathering.out");

int n, m;
vi g[maxn+5], fii[maxn+5], tour, g2[maxn+5];
int rmq[2*maxn+5][ml2+5], lg[2*maxn+5], fapr[maxn+5], niv[maxn+5], ans[maxn+5];
bool ancestor[maxn+5], viz[maxn+5];

void dfsi (int nod, int t) {
  if (nod != 0) niv[nod] = 1+niv[t];
  for (int nn: g[nod])
    if (nn != t) fii[nod].pb(nn), dfsi(nn, nod);
}

void dfst (int nod) {
  if (fapr[nod] == -1) fapr[nod] = sz(tour);
  tour.pb(nod);
  for (int nn: fii[nod]) dfst(nn), tour.pb(nod);
}

void prelca () {
  fill(all(fapr), -1);
  dfst(0);
  int i, j;
  for (i = 2; i <= sz(tour); i++) lg[i] = 1+lg[i>>1];
  for (i = 0; i < sz(tour); i++) rmq[i][0] = tour[i];
  for (j = 1; j <= lg[sz(tour)]; j++)
    for (i = 0; i+(1<<j)-1 < sz(tour); i++) { ///-1!!
      rmq[i][j] = rmq[i+(1<<(j-1))][j-1];
      if (niv[rmq[i][j]] > niv[rmq[i][j-1]]) rmq[i][j] = rmq[i][j-1];
    }
}

int lca (int a, int b) {
  if (fapr[a] > fapr[b]) swap(a, b);
  int ile = lg[fapr[b]-fapr[a]+1];
  int x = rmq[fapr[a]][ile], y = rmq[fapr[b]-(1<<ile)+1][ile];///1<<!
  if (niv[x] < niv[y]) return x;
  return y;
}

int dist (int a, int b) {
  int c = lca(a, b);
  return niv[a] + niv[b] - 2*niv[c];
}

void dfs (int nod, int prew, int b) {
  if (ans[nod] == 0) return;
  if (dist(nod, b) < dist(prew, b)) return;
  ans[nod] = 0;
  for (int nn: g[nod]) dfs(nn, nod, b);
}

void special () {
  for (int i = 0; i < n; i++) fout << 0 << '\n';
  exit(0);
}

void dfsc (int nod) {
  viz[nod] = 1;
  ancestor[nod] = 1;
  for (int nn: g2[nod]) {
    if (ancestor[nn]) special();
    dfsc(nn);
  }
  ancestor[nod] = 0;
}

int main () {
  fin >> n >> m;
  int i, a, b;
  for (i = 0; i < n-1; i++) {
    fin >> a >> b; a--; b--;
    g[a].pb(b);
    g[b].pb(a);
  }
  dfsi(0, -1);
  prelca();
  fill(all(ans), 1);
  for (i = 0; i < m; i++) {
    fin >> a >> b; a--; b--;
    g2[a].pb(b);
    ans[a] = 0;
    for (int nn: g[a]) dfs (nn, a, b);
  }
  for (i = 0; i < n; i++)
    if (!viz[i]) dfsc (i);
  for (i = 0; i < n; i++) fout << ans[i] << '\n';
  fin.close(); fout.close();
  return 0;
}