Submission #948413

#	Time	Username	Problem	Language	Result	Execution time	Memory
948413		vjudge1	Pipes (CEOI15_pipes)	C++17	30 / 100	87 ms	16268 KiB

pipes

#include <bits/stdc++.h>
using namespace std;
//#define int long long
#define all(x) x.begin(), x.end()
#define size(x) (int)x.size()

const short N = 5000;

vector<pair<short, int>> g[N];
bool vis[N];
int tin[N], fup[N], timer;
vector<pair<short, short>> bridges;
 
void dfs(short v, short p = -1, int idx = -1) {
  vis[v] = true;
  tin[v] = fup[v] = ++timer;
  for (auto [to, new_idx] : g[v]) {
    if (idx == new_idx) continue;
    else if (vis[to]) fup[v] = min(fup[v], tin[to]);
    else {
      dfs(to, v, new_idx);
      fup[v] = min(fup[v], fup[to]);
      if (fup[to] > tin[v]) {
        bridges.push_back({v, to});
      }
    }
  }
}

signed main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  short n; int m;
  cin >> n >> m;
  for (int i = 0; i < m; ++i) {
    short a, b; cin >> a >> b;
    a--, b--;
    g[a].push_back({b, i});
    g[b].push_back({a, i});
  }
  for (short i = 0; i < n; ++i) {
    if (!vis[i]) dfs(i);
  }
  for (auto [a, b] : bridges) {
    cout << a + 1 << ' ' << b + 1 << '\n';
  }
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10