oj.uz

Submission #41870

# Submission time Handle Problem Language Result Execution time Memory
41870 2018-02-21T18:38:12 Z octopuses Pipes (CEOI15_pipes) C++14
100 / 100
 2939 ms 8308 KB 
//Giorgi Kldiashvili

#include <bits/stdc++.h>

#define ll long long
#define M 1000000007ll

using namespace std;
const int N = 100001;

int n, m, x, y, timer;

int p[N], P[N], c[N], d[N], in[N], out[N];
vector < int > G[N];
bool used[N];

int Parent(int x)
{
  if(P[x] == x)
    return x;
  return P[x] = Parent(P[x]);
}

void go(int v)
{
  c[v] = d[v] = in[v] = ++ timer;
  used[v] = true;
  for(int i = 0; i < G[v].size(); ++ i)
  {
    if(used[G[v][i]])
      continue;
    p[G[v][i]] = v;
    go(G[v][i]);
  }
  out[v] = timer;
}
void dfs(int v)
{
  used[v] = true;
  for(int i = 0; i < G[v].size(); ++ i)
  {
    if(used[G[v][i]])
      continue;
    dfs(G[v][i]);
    c[v] = min(c[v], c[G[v][i]]);
    d[v] = max(d[v], d[G[v][i]]);
  }
  if(p[v] == 0)
    return;
  if(c[v] >= in[v] && d[v] <= out[v])
    printf("%d %d\n", v, p[v]);
}

int main()
{
  //freopen("input.txt", "r", stdin);
  //freopen("output.txt", "w", stdout);

  scanf("%d %d", &n, &m);

  for(int i = 1; i <= n; ++ i)
    P[i] = i;

  while(m --)
  {
    scanf("%d %d", &x, &y);
    if(Parent(x) == Parent(y))
      continue;
    P[Parent(x)] = y;
    G[x].push_back(y);
    G[y].push_back(x);
  }

  for(int i = 1; i <= n; ++ i)
  {
    if(used[i]) continue;
    go(i);
  }
  rewind(stdin);

  scanf("%d %d", &n, &m);
  for(int i = 1; i <= n; ++ i)
    P[i] = i, used[i] = 0;
  while(m --)
  {
    scanf("%d %d", &x, &y);
    if(Parent(x) == Parent(y))
    {
      c[x] = min(c[x], in[y]);
      d[x] = max(d[x], in[y]);
      d[y] = max(d[y], in[x]);
      c[y] = min(c[y], in[x]);
      continue;
    }
    P[Parent(x)] = y;
  }
  for(int i = 1; i <= n; ++ i)
  {
    if(used[i]) continue;
    dfs(i);
  }
}

Compilation message

pipes.cpp: In function 'void go(int)':
pipes.cpp:28:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < G[v].size(); ++ i)
                  ~~^~~~~~~~~~~~~
pipes.cpp: In function 'void dfs(int)':
pipes.cpp:40:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < G[v].size(); ++ i)
                  ~~^~~~~~~~~~~~~
pipes.cpp: In function 'int main()':
pipes.cpp:59:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &n, &m);
   ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:66:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &x, &y);
     ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:81:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &n, &m);
   ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:86:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &x, &y);
     ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

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

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 2944 KB Output is correct
2 Correct 10 ms 2976 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 222 ms 2852 KB Output is correct
2 Correct 222 ms 2844 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 391 ms 3200 KB Output is correct
2 Correct 574 ms 3264 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 636 ms 3948 KB Output is correct
2 Correct 546 ms 4388 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 839 ms 6648 KB Output is correct
2 Correct 1044 ms 6628 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1453 ms 7228 KB Output is correct
2 Correct 1349 ms 7300 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1794 ms 8184 KB Output is correct
2 Correct 1747 ms 8304 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2244 ms 8156 KB Output is correct
2 Correct 2125 ms 8300 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2707 ms 7980 KB Output is correct
2 Correct 2939 ms 8308 KB Output is correct