oj.uz

Submission #682111

# Submission time Handle Problem Language Result Execution time Memory
682111 2023-01-15T19:06:37 Z MilosMilutinovic Pipes (CEOI15_pipes) C++14
0 / 100
 5 ms 5252 KB 
/**
 *    author:  wxhtzdy
 *    created: 15.01.2023 19:07:48
**/
#include <bits/stdc++.h>

using namespace std;

const int MAX = 100000;
const int L = 16;

int n, m;
vector<int> g[MAX];
int f[MAX];
int i;
int j;
int par[MAX];
int dep[MAX];
int jump[MAX][L];
int u;
int v;
int pu;
int pv;
int w;

void SolveFirstSubtask() {
  for (i = 0; i < m; i++) {
    cin >> u >> v;
    --u; --v;
    g[u].push_back(v);
    g[v].push_back(u);
  }             
  function<void(int, int)> Dfs = [&](int v, int pr) {
    dep[v] = dep[pr] + 1;
    f[v] = dep[v];
    for (int u : g[v]) {
      if (u == pr) {
        continue;
      }
      if (!dep[u]) {
        Dfs(u, v);
        f[v] = min(f[v], f[u]);
        if (f[u] > dep[v]) {
          cout << v + 1 << " " << u + 1 << '\n';
        }
      } else {
        f[v] = min(f[v], dep[u]);
      }
    }
  };
  for (int i = 0; i < n; i++) {
    if (!dep[i]) {
      Dfs(i, i);
    }
  }
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);  
  cin >> n >> m;
  if (n <= 100 && m <= 200) {
    SolveFirstSubtask();
    return 0;
  }
  assert(false);
  for (i = 0; i < n; i++) {
    par[i] = -1;
  }
  function<int(int)> get = [&](int x) {
    return par[x] < 0 ? x : par[x] = get(par[x]);
  };
  for (i = 0; i < n; i++) {
    for (j = 0; j < L; j++) {
      jump[i][j] = i;
    }
  }
  function<void(int, int)> Dfs = [&](int v, int pr) {
    dep[v] = dep[pr] + 1;
    jump[v][0] = pr;
    for (j = 1; j < L; j++) {
      jump[v][j] = jump[jump[v][j - 1]][j - 1];
    }    
    for (int u : g[v]) {
      if (u != pr) {
        Dfs(u, v);
      }
    }
  }; 
  auto LCA = [&](int u, int v) {
    if (dep[u] > dep[v]) {
      swap(u, v);
    }
    for (j = L - 1; j >= 0; j--) {
      if (dep[jump[v][j]] >= dep[u]) {
        v = jump[v][j];
      }
    }
    if (u == v) {
      return u;
    }
    for (j = L - 1; j >= 0; j--) {
      if (jump[u][j] != jump[v][j]) {
        u = jump[u][j];
        v = jump[v][j];
      }
    }
    return jump[u][0];
  };
  for (i = 0; i < m; i++) {
    cin >> u >> v;
    --u; --v;
    if (get(u) != get(v)) {
      pu = get(u);
      pv = get(v);
      if (par[pu] > par[pv]) {
        swap(pu, pv);
        swap(u, v);        
      }
      Dfs(v, u);
      g[u].push_back(v);
      g[v].push_back(u);
      par[pu] += par[pv];
      par[pv] = pu;
    } else {
      w = LCA(u, v);
      f[u] += 1;
      f[v] += 1;
      f[w] -= 2;  
    }
  }
  function<void(int, int)> Solve = [&](int v, int pr) {
    for (int u : g[v]) {
      if (u != pr) {
        Solve(u, v);
        f[v] += f[u];
      }
    }
    if (f[v] == 0 && pr != -1) {
      cout << v + 1 << " " << pr + 1 << '\n';
    }
  };
  for (i = 0; i < n; i++) {
    if (get(i) == i) {
      Solve(i, -1);
    }
  }
  return 0;
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Incorrect 2 ms 2644 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 4 ms 5204 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 4 ms 5204 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 3 ms 5204 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 4 ms 5204 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 5 ms 5204 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 4 ms 5204 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 5 ms 5252 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 4 ms 5204 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #10
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 4 ms 5204 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -