oj.uz

답안 #468705

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
468705 2021-08-29T12:25:36 Z paga2004 Mousetrap (CEOI17_mousetrap) C++14
0 / 100
 5000 ms 78568 KB 
#include <bits/stdc++.h>

#define int long long

using namespace std;

#ifdef LOCAL
#define dbg(x) cerr << x << "\n";
#else
#define dbg(x)
#endif

const int INF = 1e17;

int n, t, m;
vector<int> scores;
vector<vector<int>> g;
vector<int> depths;

int dfs1(int v, int p) {
  depths[v] = depths[p] + max(0ll, (int)g[v].size() - 2);
  if (v == t) {
    depths[v] = 0;
  }
  vector<int> besties;
  for (int w : g[v]) {
    if (w == p)
      continue;
    int thisscore = dfs1(w, v);
    if (thisscore < 0)
      continue;
    besties.push_back(dfs1(w, v));
  }
  sort(besties.begin(), besties.end());
  int score = besties.size();
  if ((int)g[v].size() == 1)
    score = 1;
  if (v == t) {
    score = 0;
  }
  if (besties.size() >= 2) {
    score += besties[besties.size() - 2];
  }
  scores[v] = score;
  if (v == m) {
    return -score;
  }
  return score;
}

int dfs2(int v, int p) {
  dbg("v " << v << " blocks " << depths[p]);
  int score = -INF;
  if (v == m) {
    score = 0;
    dbg("heerer " << depths[p] + scores[v]);
    for (int w : g[v]) {
      if (w == p)
        continue;
      score = max(depths[v] + scores[w] + 1, score);
    }

    dbg("Score at m: " << score);
    return score;
  }
  for (int w : g[v]) {
    if (w == p)
      continue;
    score = max(dfs2(w, v), score);
    dbg("current score #" << w << ": " << score);
  }
  if (score != -INF) {
    return max(score, depths[p] - 2 + scores[v]);
  }
  return -INF;
}

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

  cin >> n >> t >> m;
  t--;
  m--;
  if (t == m) {
    cout << "0\n";
    exit(0);
  }

  g.resize(n);
  scores.resize(n);
  depths.resize(n);
  for (int i = 0; i < n - 1; i++) {
    int a, b;
    cin >> a >> b;
    a--;
    b--;
    g[a].push_back(b);
    g[b].push_back(a);
  }

  depths[t] = 1;
  dfs1(t, t);
  dbg("scores");
  for (int i = 0; i < n; i++) {
    cout << scores[i] << " ";
  }
  cout << "\n";
  dbg("depths");
  for (int i = 0; i < n; i++) {
    cout << depths[i] << " ";
  }
  cout << "\n";

  cout << dfs2(t, t) << "\n";
}

Subtask #1
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 0 ms 204 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 5046 ms 78568 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #3
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 0 ms 204 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 0 ms 204 KB Output isn't correct
2 Halted 0 ms 0 KB -