Submission #948363

#	Time	Username	Problem	Language	Result	Execution time	Memory
948363		vjudge1	Pipes (CEOI15_pipes)	C++17	10 / 100	76 ms	8788 KiB

pipes

//#pragma GCC optimizer("03") ;
#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;
 
bool YES(bool f){ if(f) cout << "Yes\n" ; else cout << "No\n" ; return f ; }
void YES(){YES(1);}
void NO(){YES(0);}
void fopn(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
//#define ordered_set tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
#define ios ios_base::sync_with_stdio(0) ; cin.tie(0) ; cout.tie(0);
//#define int long long
#define ld long double
#define pii pair <int , int>
#define all(x) x.begin() , x.end()
#define ff first
#define ss second
#define endl '\n'
 
const int N = 5000 + 5 ;
const int inf = 1e9 ;
const int mod = 1e9 + 7 ;
const double eps = 1e-8 ;
 
template <class T>
bool chmax( T& x , const T& y ){
  bool f = 0 ;
  if ( x < y ) x = y , f = 1 ;
  return f ;
}
template <class T>
bool chmin( T &x , const T &y ){
  bool f = 0 ;
  if ( x > y ) x = y , f = 1 ;
  return f ;
}
 
//code
 
int n , m , t ;
vector <int> g[N] , vis(N) , dis(N,-1) , low(N,-1) ;

void dfs ( int v , int p ){
	vis[v] = 1 ;
	dis[v] = low[v] = ++ t ;
	for ( auto to : g[v] ){
		if ( to == p ) continue ;
		if ( vis[to] ) chmin ( low[v] , dis[to] ) ;
		if ( !vis[to] ){
			dfs ( to , v ) ;
			chmin ( low[v] , low[to] ) ;
			if ( low[to] > dis[v] )	cout << v << ' ' << to << endl ;
		}
	}
}

void solve(){
	
	cin >> n >> m ;
	for ( int i = 0 ; i < m ; i ++ ){
		int x , y ;
		cin >> x >> y ;
		g[x].push_back(y) ;
		g[y].push_back(x) ;
	} 
	for ( int i = 1 ; i <= n ; i ++ ){
		if ( !vis[i] ) dfs(i,-1) ;
	}
}

signed main(){
    ios ;
	int t = 1 ;
	//cin >> t ;
	while ( t -- ) solve() ;
}

Compilation message (stderr)

pipes.cpp: In function 'void fopn(std::string)':
pipes.cpp:11:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 | void fopn(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pipes.cpp:11:72: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 | void fopn(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                                                                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 10 / 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