oj.uz

Submission #36024

# Submission time Handle Problem Language Result Execution time Memory
36024 2017-12-04T09:16:24 Z funcsr Pipes (CEOI15_pipes) C++14
100 / 100
 3742 ms 14224 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<P> G[100000];

bool used[100000];
int R[100000], T[100000];
void dfs(int x, int pe, int r) {
  used[x] = true;
  R[x] = r;
  for (P pp : G[x]) {
    int t = pp._1;
    if (pp._2 == pe) continue;
    if (used[t]) {
      if (R[x] > R[t]) T[x]++, T[t]--;
      continue;
    }
    dfs(t, pp._2, r+1);
  }
}

void dfs2(int x, int p) {
  used[x] = true;
  for (P pp : G[x]) {
    int t = pp._1;
    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(i, M) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    if (!uf1.same(u, v)) {
      G[u].pb(P(v, i)), G[v].pb(P(u, i));
      uf1.unite(u, v);
    }
    else if (!uf2.same(u, v)) {
      G[u].pb(P(v, i)), G[v].pb(P(u, i));
      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
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2688 KB Output is correct
2 Correct 4 ms 2688 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 3200 KB Output is correct
2 Correct 11 ms 3072 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 284 ms 3104 KB Output is correct
2 Correct 275 ms 2956 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 495 ms 3756 KB Output is correct
2 Correct 583 ms 3504 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 834 ms 5368 KB Output is correct
2 Correct 710 ms 5172 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1211 ms 10684 KB Output is correct
2 Correct 1046 ms 8368 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1872 ms 11908 KB Output is correct
2 Correct 1714 ms 9156 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2355 ms 14224 KB Output is correct
2 Correct 2282 ms 10936 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2959 ms 14092 KB Output is correct
2 Correct 2826 ms 10868 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3742 ms 13472 KB Output is correct
2 Correct 3561 ms 10708 KB Output is correct