oj.uz

답안 #35987

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
35987 2017-12-04T05:21:42 Z funcsr Pipes (CEOI15_pipes) C++14
0 / 100
 2929 ms 7744 KB 
#include <bitset>
#include <cassert>
#include <vector>
#define rep(i, n) for (int i=0; i<(n); i++)
#define INF 1145141919
#define pb push_back

using namespace std;
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];

int R[100000];
int U[17][100000];
void dfs(int x, int p, int r) {
  R[x] = r;
  U[0][x] = p;
  for (int t : G[x]) {
    if (t == p) continue;
    dfs(t, x, r+1);
  }
}

inline int lca(int x, int y) {
  if (R[x] < R[y]) swap(x, y);
  return y;
  /*
  for (int b=16; b>=0; b--) if ((R[x]-R[y])>>b) x = U[b][x];
  if (x == y) return x;
  for (int b=16; b>=0; b--) if (U[b][x] != U[b][y]) x = U[b][x], y = U[b][y];
  return U[0][x];
  */
}

int T[100000];
int dfs2(int x, int p) {
  for (int t : G[x]) {
    if (t == p) continue;
    T[x] += dfs2(t, x);
  }
  if (p != -1 && T[x] == 0) printf("%d %d\n", x+1, p+1);
  int ret = T[x];
  T[x] = INF;
  return ret;
}


signed main() {
  auto f = fopen("/dev/stdin", "r");
  fscanf(f, "%d %d", &N, &M);
  auto uf = new UnionFind(N);
  auto backward = new bitset<6000000>();
  rep(i, M) {
    int u, v;
    fscanf(f, "%d %d", &u, &v);
    u--, v--;
    if (!uf->same(u, v)) {
      backward->set(i);
      uf->unite(u, v);
      G[u].pb(v);
      G[v].pb(u);
    }
  }
  delete uf;
  rep(i, N) R[i] = -1;
  rep(i, N) if (R[i] == -1) dfs(i, -1, 0);
  /*
  rep(k, 16) rep(i, N) {
    if (U[k][i] == -1) U[k+1][i] = -1;
    U[k+1][i] = U[k][U[k][i]];
  }
  */

  fseek(f, 0, 0);
  int nn, nm;
  fscanf(f, "%d %d", &nn, &nm);
  assert(N == nn && M == nm);
  rep(i, M) {
    int u, v;
    fscanf(f, "%d %d", &u, &v);
    u--, v--;
    if (!backward->test(i)) {
      T[u]++;
      T[v]++;
      T[lca(u, v)]-=2;
    }
  }
  delete backward;
  rep(i, N) if (T[i] != INF) dfs2(i, -1);
  return 0;
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:68:9: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   fscanf(f, "%d %d", &N, &M);
   ~~~~~~^~~~~~~~~~~~~~~~~~~~
pipes.cpp:73:11: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     fscanf(f, "%d %d", &u, &v);
     ~~~~~~^~~~~~~~~~~~~~~~~~~~
pipes.cpp:94:9: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   fscanf(f, "%d %d", &nn, &nm);
   ~~~~~~^~~~~~~~~~~~~~~~~~~~~~
pipes.cpp:98:11: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     fscanf(f, "%d %d", &u, &v);
     ~~~~~~^~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 4 ms 3456 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 9 ms 3692 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #3
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 265 ms 3584 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 393 ms 3880 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 633 ms 4448 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #6
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 841 ms 6424 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 1362 ms 6880 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 1937 ms 7732 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 2283 ms 7744 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #10
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 2929 ms 7492 KB Wrong number of edges
2 Halted 0 ms 0 KB -