oj.uz

답안 #711646

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
711646 2023-03-17T10:34:31 Z Pety Pipes (CEOI15_pipes) C++14
0 / 100
 37 ms 26720 KB 
#include <bits/stdc++.h>

using namespace std;

int n, m, x, y, sz[100002], p[100002], dp[20][100002], depth[100002];
vector<vector<int>>v[100002];
vector<int>G[100002];

int find (int x) {
  if (p[x] == x)
    return x;
  return p[x] = find(p[x]);
}

void merge (int x, int y) {
  int px = find(x);
  int py = find(y);
  if (px == py)
    return;

  if (sz[px] > sz[py]) {
    swap(x, y);
    swap(px, py);
  }
  p[px] = py;
  sz[py] += sz[px];
  for (int i = y; i; i = dp[0][i]) {
    for (int j = 0; (1 << j) < n; j++) {
      int lvl = (1 << j) - 1 - (depth[y] - depth[i]);
      if (lvl >= 0 && lvl < v[px].size()) 
        for (auto it : v[px][lvl])
          dp[j][it] = i;
    }
  }
  for (int i = 0; i < v[px].size(); i++) {
    while (depth[y] + i + 1 >= v[py].size())
      v[py].push_back({});
    for (auto it : v[px][i]) {
      assert(depth[it] == i);
      v[py][depth[y] + i + 1].push_back(it);
      depth[it]+=depth[y] + 1;
    }
  }
}

int lca (int x, int y) {
  if (depth[x] > depth[y])
    swap(x, y);
  int d = depth[y] - depth[x];
  for (int i = 0; (1 << i) <= d; i++)
    if (d & (1 << i))
      y = dp[i][y];
  if (x == y)
    return x;
  for (int i = 19; i >= 0; i--)
    if (dp[i][x] != dp[i][y]) {
      x = dp[i][x];
      y = dp[i][y];
    }
  return dp[0][x];
}

int add[100002], viz[100002];

void dfs (int x, int par) {
  //cout << x << "\n";
  viz[x] = 1;
  for (auto it : G[x]) {
    if (it == par)
      continue;
    dfs(it, x);
    add[x] += add[it];
  }
  if (add[x] == 0 && par != 0)
    cout << x << " " << par << "\n";
}

int main () 
{
  ios_base::sync_with_stdio(false);
  cin.tie(0); cout.tie(0);
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    p[i] = i;
    sz[i] = 1;
    v[i].push_back({i});
  }
  for (int i = 1; i <= m; i++) {
    cin >> x >> y;
    if (find(x) == find(y)) {
      int L = lca(x, y);
      add[L] -= 2;
      add[x]++;
      add[y]++;
    }
    else {
      merge(x, y);
      assert(abs(depth[x] - depth[y]) == 1);
      if (depth[x] < depth[y]) {
        G[x].push_back(y);
      }
      else {
        G[y].push_back(x);
      }
    }
  }
  for (int i = 1; i <= n; i++)
    if (!viz[find(i)])
      dfs(find(i), 0);
  return 0;
}

Compilation message

pipes.cpp: In function 'void merge(int, int)':
pipes.cpp:30:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |       if (lvl >= 0 && lvl < v[px].size())
      |                       ~~~~^~~~~~~~~~~~~~
pipes.cpp:35:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |   for (int i = 0; i < v[px].size(); i++) {
      |                   ~~^~~~~~~~~~~~~~
pipes.cpp:36:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |     while (depth[y] + i + 1 >= v[py].size())
      |            ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 7 ms 10068 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 8 ms 10836 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #3
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 8 ms 10708 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 9 ms 11732 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 13 ms 14036 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #6
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 18 ms 21492 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 21 ms 23452 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 37 ms 26700 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 34 ms 26720 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #10
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 24 ms 25556 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -