Submission #1304881

#	Time	Username	Problem	Language	Result	Execution time	Memory
1304881		neonglitch	One-Way Streets (CEOI17_oneway)	C++20	0 / 100	1 ms	332 KiB

oneway

#include <iostream>
#include <vector>
#include <map>
using namespace std;
const int N=1e5+10;
pair<int,int> edge[N];
int h[N],lw[N],par[N];
bool vis[N],bri[N];
char dir[N];
vector<pair<int,int>> adj[N];
void dfs(int x,int pid=0)
{
	vis[x]=1;
	lw[x]=h[x];
	for(auto [y,id]:adj[x])
	{
		if(pid==id)continue;
		if(!vis[y])
		{
			h[y]=h[x]+1;
			par[y]=x;
			dfs(y,id);
			if(lw[y]<h[y])
			{
				// cout<<"Non bridge "<<id<<endl;
				bri[id]=0;
			}
			lw[x]=min(lw[x],lw[y]);
		}
		else{
			// y is ancestor of x
			// cout<<"Edge "<<id<<' '<<x<<' '<<y<<endl;
			bri[id]=0;
			lw[x]=min(lw[x],h[y]);
		}
	}
	// cout<<"At "<<x<<' '<<h[x]<<' '<<lw[x]<<endl;
}
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,m;
	cin>>n>>m;
	for(int j=1;j<=m;j++)
	{
		int x,y;
		cin>>x>>y;
		edge[j]={x,y};
		adj[x].push_back({y,j});
		adj[y].push_back({x,j});
		bri[j]=(x!=y);
	}
	for(int i=1;i<=n;i++)
	{
		if(!vis[i])dfs(i);
	}
	int p;
	cin>>p;
	map<pair<int,int>,bool> use;
	for(int i=0;i<p;i++)
	{
		int x,y;
		cin>>x>>y;
		while(x!=y)
		{
			if(h[x]>h[y])
			{
				// edge x to par[x] should be 
				use[{x,par[x]}]=1;
				x=par[x];
			}
			else{
				use[{par[y],y}]=1;
				y=par[y];
			}
		}
	}
	for(int j=1;j<=m;j++)
	{
		if(!bri[j])cout<<'B';
		else if(use[edge[j]])cout<<'R';
		else cout<<'L';
	}
	cout<<endl;
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40