Submission #146706

#	Time	Username	Problem	Language	Result	Execution time	Memory
146706		MvC	Pipes (CEOI15_pipes)	C++14	100 / 100	1493 ms	16336 KiB

pipes

#pragma GCC target("avx2")
#pragma GCC optimization("O3")
#pragma GCC optimization("unroll-loops")
#include<bits/stdc++.h>
//#include "boxes.h"
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define mkp make_pair
#define in insert
#define er erase
#define fd find
#define fr first
#define sc second
typedef long long ll;
typedef long double ld;
const ll INF=0x3f3f3f3f3f3f3f3f;
const ll llinf=(1LL<<62);
const int inf=(1<<30);
const int nmax=1e5+3;
const int mod=1e9+7;
using namespace std;
int n,m,i,x,y,p[nmax],p1[nmax],sz[nmax],sz1[nmax],fup[nmax],fin[nmax],tin,pr[nmax];
vector<pair<int,int> >a[nmax];
int fnd(int x)
{
	if(p[x]==x)return x;
	return p[x]=fnd(p[x]);
}
void uni(int x,int y)
{
	a[x].pb(mkp(y,++tin));
	a[y].pb(mkp(x,tin));
	x=fnd(x),y=fnd(y);
	if(sz[x]<sz[y])swap(x,y);
	sz[x]+=sz[y];
	p[y]=x;
}
int fnd1(int x)
{
	if(p1[x]==x)return x;
	return p1[x]=fnd1(p1[x]);
}
void uni1(int x,int y)
{
	a[x].pb(mkp(y,++tin));
	a[y].pb(mkp(x,tin));
	x=fnd1(x),y=fnd1(y);
	if(sz1[x]<sz1[y])swap(x,y);
	sz1[x]+=sz1[y];
	p1[y]=x;
}
void dfs(int x)
{
	fin[x]=fup[x]=++tin;
	for(int i=0;i<a[x].size();i++)
	{
		if(a[x][i].sc==pr[x])continue;
		if(!fin[a[x][i].fr])
		{
			pr[a[x][i].fr]=a[x][i].sc;
			dfs(a[x][i].fr);
			fup[x]=min(fup[x],fup[a[x][i].fr]);
			if(fup[a[x][i].fr]>fin[x])cout<<x<<" "<<a[x][i].fr<<'\n';
		}
		else fup[x]=min(fup[x],fin[a[x][i].fr]);
	}
}
int main()
{
	//freopen("sol.in","r",stdin);
	//freopen("sol.out","w",stdout);
	//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
	ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
	cin>>n>>m;
	for(i=1;i<=n;i++)
	{
		p[i]=i;
		sz[i]=1;
		p1[i]=i;
		sz1[i]=1;
	}
	while(m--)
	{
		cin>>x>>y;
		if(fnd(x)!=fnd(y))
		{
			uni(x,y);
			//cout<<x<<" "<<y<<endl;
		}
		else if(fnd1(x)!=fnd1(y))
		{
			uni1(x,y);
			//cout<<x<<" "<<y<<endl;
		}
	}
	//cout<<endl;
	for(i=1;i<=n;i++)
	{
		if(fin[i])continue;
		dfs(i);
	}
	return 0;
}

Compilation message (stderr)

pipes.cpp:2:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization("O3")
 
pipes.cpp:3:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization("unroll-loops")
 
pipes.cpp: In function 'void dfs(int)':
pipes.cpp:55:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<a[x].size();i++)
              ~^~~~~~~~~~~~

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