Submission #531911

#	Time	Username	Problem	Language	Result	Execution time	Memory
531911		Alex_tz307	Bitaro’s Party (JOI18_bitaro)	C++17	100 / 100	1492 ms	68976 KiB

bitaro

#include <bits/stdc++.h>

using namespace std;

const int kN = 2e5;
const int bucket = 50;
vector<int> gt[1 + kN];
vector<pair<int, int>> paths[1 + kN];
int vis[1 + kN], b[kN], dp[1 + kN];
bitset<1 + kN> blocked;

void maxSelf(int &x, int y) {
  if (x < y) {
    x = y;
  }
}

void testCase() {
  int n, m, q;
  cin >> n >> m >> q;
  for (int i = 0; i < m; ++i) {
    int u, v;
    cin >> u >> v;
    gt[v].emplace_back(u);
  }
  for (int u = 1; u <= n; ++u) {
    vector<pair<int, int>> aux{{0, u}};
    for (int v : gt[u]) {
      for (auto it : paths[v]) {
        aux.emplace_back(it.first + 1, it.second);
      }
    }
    sort(aux.begin(), aux.end(), greater<pair<int, int>>());
    for (auto it : aux) {
      if (vis[it.second] != u) {
        paths[u].emplace_back(it);
        if ((int)paths[u].size() == bucket) {
          break;
        }
        vis[it.second] = u;
      }
    }
  }
  for (int i = 0; i < q; ++i) {
    int s, m;
    cin >> s >> m;
    for (int j = 0; j < m; ++j) {
      cin >> b[j];
      blocked[b[j]] = true;
    }
    if (bucket <= m) {
      for (int u = 1; u <= s; ++u) {
        if (blocked[u]) {
          dp[u] = -1;
        } else {
          dp[u] = 0;
        }
        for (int v : gt[u]) {
          if (dp[v] != -1) {
            maxSelf(dp[u], dp[v] + 1);
          }
        }
      }
      cout << dp[s] << '\n';
    } else {
      int ans = -1;
      for (auto it : paths[s]) {
        if (!blocked[it.second]) {
          ans = it.first;
          break;
        }
      }
      cout << ans << '\n';
    }
    for (int j = 0; j < m; ++j) {
      blocked[b[j]] = false;
    }
  }
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int tests = 1;
  for (int tc = 0; tc < tests; ++tc) {
    testCase();
  }
  return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 86 / 86