Submission #3767923

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;
#ifdef _DEBUG
#define _GLIBCXX_DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define ll long long
#define ll1 1ll
#define ONE 1ll
#define DBG 1
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define rrep(i, a, b) for (int i = (b)-1; i >= (a); i--)
#define loop(n) rep(loop, (0), (n))
#define all(c) begin(c), end(c)
const int INF =
    sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
const double PI = acos(-1);
const double EPS = 1e-9;
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
using pii = pair<int, int>;
// template<class T> ostream &operator<<(ostream &os,T &t){dump(t);return os;}
template <typename T, typename S>
istream &operator>>(istream &is, pair<T, S> &p) {
  is >> p.first >> p.second;
  return is;
}
template <typename T, typename S>
ostream &operator<<(ostream &os, pair<T, S> &p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T> void printvv(const vector<vector<T>> &v) {
  cerr << endl;
  rep(i, 0, v.size()) rep(j, 0, v[i].size()) {
    if (typeid(v[i][j]).name() == typeid(INF).name() and v[i][j] == INF) {
      cerr << "INF";
    } else
      cerr << v[i][j];
    cerr << (j == v[i].size() - 1 ? '\n' : ' ');
  }
  cerr << endl;
}
/*
   typedef __int128_t Int;
   std::ostream &operator<<(std::ostream &dest, __int128_t value) {
   std::ostream::sentry s(dest);
   if (s) {
   __uint128_t tmp = value < 0 ? -value : value;
   char buffer[128];
   char *d = std::end(buffer);
   do {
   --d;
 *d = "0123456789"[tmp % 10];
 tmp /= 10;
 } while (tmp != 0);
 if (value < 0) {
 --d;
 *d = '-';
 }
 int len = std::end(buffer) - d;
 if (dest.rdbuf()->sputn(d, len) != len) {
 dest.setstate(std::ios_base::badbit);
 }
 }
 return dest;
 }

 __int128 parse(string &s) {
 __int128 ret = 0;
 for (int i = 0; i < s.length(); i++)
 if ('0' <= s[i] && s[i] <= '9')
 ret = 10 * ret + s[i] - '0';
 return ret;
 }
 */

#ifndef _DEBUG
#define printvv(...)
#endif
void YES(bool f) { cout << (f ? "YES" : "NO") << endl; }
void Yes(bool f) { cout << (f ? "Yes" : "No") << endl; }
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
struct SCC {
  int V;
  vector<vector<int>> G, rG, SC;
  vector<int> vs, cmp; // post order, topological order
  vector<bool> used;

  SCC() {}
  SCC(int V) : V(V), G(V), rG(V), used(V), cmp(V) {}
  void add_arc(int s, int t) {
    G[s].push_back(t);
    rG[t].push_back(s);
  }
  void dfs(int v) {
    used[v] = true;
    for (int i : G[v]) {
      if (not used[i])
        dfs(i);
    }
    vs.push_back(v);
  }
  void rdfs(int v, int k) {
    used[v] = true;
    cmp[v] = k;
    for (int i : rG[v]) {
      if (not used[i])
        rdfs(i, k);
    }
  }
  int scc() {
    fill(all(used), false);
    vs.clear();
    SC.clear();
    rep(v, 0, V) {
      if (not used[v])
        dfs(v);
    }
    fill(all(used), false);
    int k = 0;
    rrep(i, 0, vs.size()) {
      if (not used[vs[i]])
        rdfs(vs[i], k++);
    }
    SC.resize(k);
    rep(i, 0, V) { SC[cmp[i]].emplace_back(i); }
    rep(i, 0, SC.size()) { sort(all(SC[i])); }
    return k;
  }
  void fill_dist(int v, int d, vector<int> &dist) {
    if (used[v])
      return;
    used[v] = true;
    dist[v] = d;
    for (auto u : G[v]) {
      fill_dist(u, d + 1, dist);
    }
  }
  void solve() {
    scc();
    fill(all(used), false);
    vector<int> dist(V, -1);
    fill_dist(SC[0][0], 0, dist);
    int ans = *max_element(all(dist));
    for (auto u : SC[0]) {
      ans += not used[u];
    }
    cout << ans << endl;
  }
};
signed main(signed argc, char *argv[]) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(12);

  int N;
  cin >> N;
  SCC g(N);
  rep(i, 0, N - 1) {
    int a, b, t;
    cin >> a >> b >> t;
    a--, b--;
    g.add_arc(a, b);
    if (t == 2) {
      g.add_arc(b, a);
    }
  }
  g.solve();

  return 0;
}

Submission Info

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