oj.uz

Submission #36023

# Submission time Handle Problem Language Result Execution time Memory
36023 2017-12-04T09:13:23 Z funcsr Pipes (CEOI15_pipes) C++14
20 / 100
 3682 ms 12108 KB 
#include <iostream>
#include <fstream>
#include <bitset>
#include <cassert>
#include <vector>
#define rep(i, n) for (int i=0; i<(n); i++)
#define INF 1145141919
#define pb push_back
#define _1 first
#define _2 second

using namespace std;
typedef pair<int, int> P;

struct UnionFind {
  int U[100000];
  UnionFind(int N) {
    rep(i, N) U[i] = i;
  }
  int find(int x) {
    if (U[x] == x) return x;
    return U[x] = find(U[x]);
  }
  void unite(int x, int y) {
    x = find(x), y = find(y);
    if (x == y) return;
    U[x] = y;
  }
  bool same(int x, int y) {
    return find(x) == find(y);
  }
};

int N, M;
vector<int> G[100000];

bool used[100000];
int R[100000], T[100000];
void dfs(int x, int p, int r) {
  used[x] = true;
  R[x] = r;
  for (int t : G[x]) {
    if (t == p) continue;
    if (used[t]) {
      if (R[x] > R[t]) T[x]++, T[t]--;
      continue;
    }
    dfs(t, x, r+1);
  }
}

void dfs2(int x, int p) {
  used[x] = true;
  for (int t : G[x]) {
    if (t == p || used[t]) continue;
    dfs2(t, x);
    T[x] += T[t];
  }
  if (p != -1 && T[x] == 0) cout << x+1 << " " << p+1 << "\n";
}


signed main() {
  cin >> N >> M;
  UnionFind uf1(N), uf2(N);
  rep(_, M) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    if (!uf1.same(u, v)) {
      G[u].pb(v), G[v].pb(u);
      uf1.unite(u, v);
    }
    else if (!uf2.same(u, v)) {
      G[u].pb(v), G[v].pb(u);
      uf2.unite(u, v);
    }
  }
  rep(i, N) used[i] = false;
  rep(i, N) if (!used[i]) dfs(i, -1, 0);
  rep(i, N) used[i] = false;
  rep(i, N) if (!used[i]) dfs2(i, -1);
  return 0;
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2688 KB Output is correct
2 Incorrect 3 ms 2688 KB Wrong number of edges

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 3072 KB Output is correct
2 Incorrect 11 ms 2944 KB Wrong number of edges

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 293 ms 3024 KB Output is correct
2 Incorrect 304 ms 2936 KB Wrong number of edges

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 511 ms 3676 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 848 ms 4896 KB Output is correct
2 Correct 727 ms 4716 KB Output is correct

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1171 ms 9288 KB Output is correct
2 Incorrect 1047 ms 6988 KB Wrong number of edges

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1915 ms 10288 KB Output is correct
2 Incorrect 1805 ms 8356 KB Wrong number of edges

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2423 ms 12100 KB Output is correct
2 Incorrect 2254 ms 9040 KB Wrong number of edges

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3078 ms 12108 KB Output is correct
2 Incorrect 2936 ms 8916 KB Wrong number of edges

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3682 ms 11600 KB Output is correct
2 Correct 3536 ms 9764 KB Output is correct