Submission #396292

#	Time	Username	Problem	Language	Result	Execution time	Memory
396292		The_Blitz	Pipes (CEOI15_pipes)	C++17	0 / 100	1391 ms	65536 KiB

pipes

// Restart
// += O(logn) ; + = O(n)
 
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp> // Including tree_order_statistics_node_update
 
#define fastio ios_base::sync_with_stdio(0);cin.tie(0)
#define fst first
#define snd second
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define sz size()
#define FORN(i,j,n) for(int i=j; i<(int)n;i++) 
#define FOR(i,n) FORN(i,0,n)
#define FORIT(i,x) for( auto i = x.begin() ; i != x.end() ; i++ )
#define MOD 998244353LL
#define MOD1 1000000007LL
#define LIM 262150
#define ones(x) __builtin_popcount(x)
#define trace(x)    cerr << #x << ": " << x << endl;
#define trace2(x, y) cerr << #x << ": " << x << " | " << #y << ": " << y << endl;
#define trace3(x, y,z) cerr << #x << ": " << x << " | " << #y << ": " << y << " | " << #z << ": " << z << endl;
#define INF 1000000000
#define in(x)  cin>>x;
#define out(x) cout<<x;
#define MAXIMO 1LL<<60

#define loga2(x) __builtin_ctzll(x)
//SOLO PARA POTENCIAS DE 2
 
using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll ;
typedef unsigned long long ull ;
typedef vector <int> vi;
typedef pair <int,int> ii;
typedef pair <int,ii> iii;
typedef vector <string> vs;
typedef vector <ii> vii;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;

vector<int> G[100005];

int g_low[100005];
int g_num[100005];

int P[2][100005];
int n,m;
int cont = 1;

void dsu(int z){
	for(int i=1; i<=n;i++){
		P[z][i] = i;
	}
}
 
int dsu_find(int z, int x){
	if(x==P[z][x]) return x;
	P[z][x] = dsu_find(z,P[z][x]);
	return P[z][x];
}
 
void dsu_uni(int z, int a , int b){
	int x = dsu_find(z,a);
	int y = dsu_find(z,b);
	if(x==y) return ;
	P[z][y] = x;
} 


void dfs(int x ,int p = -1){ // p: parent
    g_low[x]=g_num[x]=cont++; // low:component ; num:visit order

    for(int i=0;i<G[x].size();i++){
        int &v =G[x][i];
        if(g_num[v]==-1){
			
			dfs(v,x);
			/*if(g_low[v] >= g_num[x]){ // CUT-VERTEX
				//cut[x] = true;
			}*/
			
			if(g_low[v] > g_num[x]){ // BRIDGE
				//bridge.push_back({min(x,v),max(x,v)});
				cout<< x << " " << v << "\n";
			}
			g_low[x]=min(g_low[x],g_low[v]);
		}
        if(v != p){
			g_low[x]=min(g_low[x],g_num[v]);
		}
    }
	
}



void go(){
	cin>>n>>m;
	int x,y;

	FORN(i,1,n+1){
		g_low[i] = -1; g_num[i] = -1;
	}

	dsu(0);
	dsu(1);

	FOR(i,m){
		cin>>x>>y;
		if(dsu_find(0,x) != dsu_find(0,y)){
			dsu_uni(0,x,y);
		}
		else{
			if(dsu_find(1,x) != dsu_find(1,y)){
				dsu_uni(1,x,y);
			}
			else continue;
		}
		G[x].push_back(y);
        G[y].push_back(x);
	}

	for(int i=1;i<=n;i++){
		if(g_num[i] == -1) dfs(i);
	}

}


void timer(){
	clock_t begin = clock();
	go();
	clock_t end = clock();
	double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
	printf("%lf\n",time_spent);
}	

 
int main() {
  fastio;
  go();
  //timer();
  return 0;
}

Compilation message (stderr)

pipes.cpp: In function 'void dfs(int, int)':
pipes.cpp:79:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |     for(int i=0;i<G[x].size();i++){
      |                 ~^~~~~~~~~~~~

• 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