제출 #861367

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
861367		Faisal_Saqib	Pipes (CEOI15_pipes)	C++17	30 / 100	772 ms	65536 KiB

pipes

#include <iostream>
#include <algorithm>
#include <climits>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <vector>

using namespace std;

const int MAXN=1e5+1;
const int LG=17;
int pa[MAXN][LG];
int par[MAXN];
int par1[MAXN];
int h[MAXN];
int Up[MAXN];
bool vis[MAXN];
vector<int> ma[MAXN];
int get1(int a)
{
	return ((par1[a]==a)?a:par1[a]=get1(par1[a]));
}
void join1(int a,int b)
{
	a=get1(a);
	b=get1(b);
	if(a!=b)
		par1[a]=b;
}
int get(int a)
{
	return ((par[a]==a)?a:par[a]=get(par[a]));
}
bool join(int a,int b)
{
	int oa=a;
	int ob=b;
	a=get(a);
	b=get(b);
	if(a!=b)
	{
		par[a]=b;
		return 1;
	}
	return 0;
}
void dfs(int x,int p)
{
	// cout<<x<<' '<<p<<endl;
	pa[x][0]=p;
	for(int j=1;j<LG;j++)
		pa[x][j]=pa[pa[x][j-1]][j-1];
	h[x]=h[p]+1;
	for(auto y:ma[x])
		if(y!=p)
			dfs(y,x);
}
int lca(int x,int y)
{
	if(h[x]>h[y])
		swap(x,y);
	for(int j=LG-1;j>=0;j--)
		if(h[x]<=h[pa[y][j]])
			y=pa[y][j];
	if(x==y)
		return x;
	for(int j=LG-1;j>=0;j--)
		if(pa[x][j]!=pa[y][j])
		{
			x=pa[x][j];
			y=pa[y][j];
		}
	return pa[x][0];
}
void solve(int x,int p=-1)
{
	vis[x]=1;
	for(auto y:ma[x])
	{
		if(y!=p)
		{
			solve(y,x);
		}
	}
	for(auto y:ma[x])
	{
		if(y!=p)
		{
			if(h[Up[x]]>h[Up[y]])
			{
				Up[x]=Up[y];
			}
			if(Up[y]==y)
			{
				cout<<x<<' '<<y<<endl;
			}
		}
	}
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=n;i++)
    	par[i]=par1[i]=Up[i]=i;
    for(int i=0;i<m;i++)
    {
    	int x,y;
    	cin>>x>>y;
    	if(join(x,y))
    	{
    		// cout<<"Tree Edge "<<x<<' '<<y<<endl;
    		ma[x].push_back(y);
    		ma[y].push_back(x);
    	}
    	else
    	{
    		// cout<<"Cycle Edge "<<x<<' '<<y<<endl;
    		join1(x,y);
    	}
    }
    // cout<<"Tree Input:\n";
    for(int i=1;i<=n;i++)
    	if(pa[i][0]==0)
		    dfs(i,i);
	// cout<<"Cycle Input:"<<endl;
    for(int y=1;y<=n;y++)
    {
    	int x=get1(y);
    	// cout<<y<<' '<<x<<endl;
    	int c=lca(x,y);
		if(h[Up[x]]>h[c])
		{
			Up[x]=c;
		}
		if(h[Up[y]]>h[c])
		{
			Up[y]=c; 
		}
    }
    // cout<<"Bridge Edges:\n";
    for(int i=1;i<=n;i++)
    	if(!vis[i])
		    solve(i);
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

pipes.cpp: In function 'bool join(int, int)':
pipes.cpp:38:6: warning: unused variable 'oa' [-Wunused-variable]
   38 |  int oa=a;
      |      ^~
pipes.cpp:39:6: warning: unused variable 'ob' [-Wunused-variable]
   39 |  int ob=b;
      |      ^~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 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