Submission #28715

#	Time	Username	Problem	Language	Result	Execution time	Memory
28715		rondojim	Pipes (CEOI15_pipes)	C++14	0 / 100	2406 ms	65536 KiB

pipes

#include <stdio.h>
#include <vector>
#include <algorithm>
#include <set>

using namespace std;

const int MAXN = 8e4 + 5;
typedef pair<int, int> edge;

vector<int> adj[MAXN];
bool vis[MAXN];
int num[MAXN], low[MAXN], pos = 1, N, M;
vector<edge> bridges;

void dfs(int u, int p){
  vis[u] = true;
  num[u] = pos++;
  low[u] = num[u];
  for(int v : adj[u]){
    if(vis[v] == false){
      dfs(v, u);
      low[u] = min(low[u], low[v]);
      if(low[v] > num[u]) bridges.push_back((edge){min(v,u),max(v,u)});
    }
    else if(v != p) low[u] = min(low[u], num[v]);
  }
}

int main(){
  scanf("%d %d", &N, &M);
  int a, b;
  set<edge> S;
  while(M--){
    scanf("%d %d", &a, &b);
    int aa = min(a, b), bb = max(a, b);
    edge p = {aa, bb};
    if(S.find(p) != S.end()) continue;
    S.insert(p);
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
  for(int i=1; i<=N; ++i) if(!vis[i]) dfs(i, -1);
  for(int i=0; i<bridges.size(); ++i) printf("%d %d\n", bridges[i].first, bridges[i].second);
  return 0;
}
    
  

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:44:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0; i<bridges.size(); ++i) printf("%d %d\n", bridges[i].first, bridges[i].second);
                ~^~~~~~~~~~~~~~~
pipes.cpp:31:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &N, &M);
   ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:35:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &a, &b);
     ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10