Submission #1027304

#	Time	Username	Problem	Language	Result	Execution time	Memory
1027304		anHiep	One-Way Streets (CEOI17_oneway)	C++14	100 / 100	81 ms	35780 KiB

oneway

#include<bits/stdc++.h>
#ifdef LOCAL
#include "D:\debug.h"
#else
#define cebug(...) "Orz_chUoNgnn_khanhtb_0x2ee08"
#endif

using namespace std;

#define fi first 
#define se second
#define pb push_back
#define ll long long
#define ii pair<int, int>
#define vi vector<int> 
#define vll vector<ll>
#define vii vector<ii>
#define cd complex<double>
const ll mod = 1e9 + 7;
const ll INF = 1e18L + 5;
const double PI = acos(-1);
const int block = 320;
const int N = 2e5;
int tc, tt = 1;

int n, m, u, v, p;
ii ans[N + 5];

struct edge {
    int v, id, x, y;
};
vector<edge> g[N + 5];
vii e;

namespace sub1 {
    bool ck() {
        return true;
    }

    int tin[N + 5], tout[N + 5], low[N + 5], tdfs = 0;
    int p[N + 5][20];
    int mark[N + 5];
    int vis[N + 5];
    int comp[N + 5], curcomp = 0;
    bool bridge[N + 5];
    int h[N + 5];
    int dp[N + 5];
    int s, t;
    vector<edge> adj[N + 5];

    void find_bridge(int u ,int par) {
        tin[u] = low[u] = ++tdfs;
        vis[u] = true;
        for(auto v: g[u])
            if(v.v != par) {
                if(!vis[v.v]) {
                    find_bridge(v.v, u);
                    low[u] = min(low[u], low[v.v]);
                    if(low[v.v] > tin[u])
                        bridge[v.id] = true;
                }
                else low[u] = min(low[u], tin[v.v]);
            }
        tout[u] = tdfs;
    }

    void find_comp(int u, int par) {
        vis[u] = true;
        comp[u] = curcomp;
        for(auto v: g[u])
            if(v.v != par && !vis[v.v] && !bridge[v.id])
                find_comp(v.v, u);
     }

    void dfs(int u, int par) {
        vis[u] = true;
        for(auto v: adj[u])
            if(v.v != par) {
                v.x = u;
                v.y = v.v;
                dfs(v.v, u);
            }
    }

    void cal(int u, int par) {
        vis[u] = true;
        for(auto v: adj[u])
            if(v.v != par) {
                cal(v.v, u);
                dp[u] += dp[v.v];
                if(dp[v.v] > 0) ans[v.id] = {v.y, v.x};
                if(dp[v.v] < 0) ans[v.id] = {v.x, v.y};
            }
    }

    void sol() {
        memset(vis, 0, sizeof(vis));
        for(int i=1; i<=n; i++)
            if(!vis[i]) {
                tdfs = 0;
                find_bridge(i, -1);
            }
        memset(vis, 0, sizeof(vis));
        for(int i=1; i<=n; i++)
            if(!vis[i]) {
                curcomp++;
                find_comp(i, -1);
            }
        for(int i=1; i<=m; i++)
            if(bridge[i]) {
                int u = e[i - 1].fi;
                int v = e[i - 1].se;
                if(comp[u] != comp[v]) {
                    adj[comp[u]].pb({comp[v], i, u, v});
                    adj[comp[v]].pb({comp[u], i, v, u});
                }
            }

        memset(vis, 0, sizeof(vis));
        for(int i=1; i<=n; i++) 
            if(!vis[i]) 
                dfs(i, -1);

        int q;
        cin>>q;
        for(int i=1; i<=q; i++) {
            cin>>s>>t;
            dp[comp[s]]++;
            dp[comp[t]]--;
        }
        memset(vis, 0, sizeof(vis));
        for(int i=1; i<=n; i++) {
            if(!vis[i]) cal(i, -1);
        }
        for(int i=1; i<=m; i++) {
            if(ans[i].fi < 0 || !bridge[i]) {
                cout<<"B";
            }
            else {
                cout<<(ans[i] == e[i - 1] ? "R" : "L");
            }
        }
    }
}

void solve() {
    cin>>n>>m;
    for(int i=1; i<=m; i++) {
        cin>>u>>v;
        ans[i] = {-1, -1};
        e.pb({u, v});
        g[u].pb({v, i, -1, -1});
        g[v].pb({u, i, -1, -1});
    }
    if(sub1::ck()) {sub1::sol(); return;}
}
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    for(tc=1; tc<=tt; tc++) solve();
    cerr<<"\nTime elapsed: "<<1000.0*clock()/CLOCKS_PER_SEC<<" ms.\n";
    return 0;
}

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