제출 #1027554

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1027554		vjudge1	One-Way Streets (CEOI17_oneway)	C++17	100 / 100	69 ms	43856 KiB

oneway

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,fma")
#define ll long long
#define pb push_back
#define eb emplace_back
#define pu push
#define ins insert
#define bruh ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define ff(x,a,b,c) for (auto x=a;x<=b;x+=c)
#define fd(x,a,b,c) for (auto x=a;x>=b;x-=c)
#define int ll

using namespace std;
//mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());

typedef pair<int, int> ii;
const int N = 2e5+5;
const int mod = 1e9+7;
const int INF = 1e18;
using cd = complex<double>;
const long double PI = acos(-1);
int power(int a,int b) {ll x = 1;if (a >= mod) a%=mod; while (b) {if (b & 1) x = x*a % mod;a = a*a % mod;b>>=1;}return x;} 

int n,m,p,curtime = 0,cnt = 0;
vector<pair<int,int>> adj[N],tree[N];
int num[N],low[N],idx[N],vis[N],a[N],b[N];
pair<int,int> edge[N];
vector<int> dir[N];
stack<int> st;
bool check[N];
char ans[N];

void dfs1(int u,int p)
{
    num[u] = low[u] = ++curtime;
    st.push(u);
    bool tmp = false;
    for (auto i : adj[u])
    {
        int v = i.first;
        if (v==p && !tmp) {tmp = true; continue;}
        if (!num[v]) {dfs1(v,u); low[u] = min(low[u],low[v]);}
        else low[u] = min(low[u],num[v]);
    }
    if (low[u]==num[u])
    {
        cnt++;
        int v;
        do
        {
            v = st.top();
            st.pop();
            idx[v] = cnt;
            check[v] = true;
        } while (v!=u);
    }
}

void dfs2(int u,int id)
{
    vis[u] = 1;
    for (auto i : tree[u]) 
    {
        if (!vis[i.first]) 
        {
            dfs2(i.first,i.second);
            a[u]+=a[i.first];
            b[u]+=b[i.first];
        }
    }
    if (a[u]==b[u]) ans[id] = 'B';
    else if (a[u]>b[u]) 
    {
        if(idx[edge[id].first]==u) ans[id]='R';
        else ans[id]='L';
    } else 
    {
        if(idx[edge[id].first]==u) ans[id]='L';
        else ans[id]='R';
    }
}

void solve()
{
	cin>>n>>m;
    for (int i=1;i<=m;i++)
    {
        int u,v; cin>>u>>v;
        edge[i] = {u,v};
        adj[u].pb({v,i}); adj[v].pb({u,i});
    }
    for (int i=1;i<=n;i++) if (!check[i]) dfs1(i,i);
    for (int u=1;u<=n;u++)
    {
        for (auto i : adj[u]) if (idx[u]!=idx[i.first]) tree[idx[u]].pb({idx[i.first],i.second});
    }
    cin>>p;
    for (int i=1;i<=p;i++)
    {
        int u,v; cin>>u>>v;
        if (idx[u]==idx[v]) continue;
        a[idx[u]]++; b[idx[v]]++;
    }
    for (int i=1;i<=cnt;i++) if (!vis[i]) dfs2(i,0);
    for (int i=1;i<=m;i++) 
    {
        if (!ans[i]) cout<<'B';
        else cout<<ans[i];
    }
}

signed main()
{
	bruh
	//freopen("input.inp","r",stdin);
	//freopen("output.inp","w",stdout);
	int t = 1;
	//cin>>t;
	while (t--)
	{
		solve();
		cout<<"\n";
	}
}

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