제출 #427649

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
427649		JerryLiu06	One-Way Streets (CEOI17_oneway)	C++17	100 / 100	524 ms	35672 KiB

oneway

#include <bits/stdc++.h>
 
using namespace std;
 
using ll = long long;
using db = long double;
using str = string;
 
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
 
#define mp make_pair
#define f first
#define s second

#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
 
#define lb lower_bound
#define ub upper_bound
 
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define EACH(a, x) for (auto& a : x)

const int MOD = 1e9 + 7;
const int MX = 1e5 + 10;
const ll INF = 1e18;

int N, M, P; vi adj[MX]; vpi edges;

int timer = 1; bool vis1[MX]; int in[MX], low[MX]; map<pi, bool> bridges;

int nComp = 1; int comp[MX]; vi compAdj[MX]; int val[MX], depth[MX]; bool vis2[MX];

void DFS1(int X) {
    vis1[X] = true; in[X] = low[X] = timer++;

    EACH(Y, adj[X]) {
        if (vis1[Y]) { low[X] = min(low[X], in[Y]); continue; } // Back Edge
        
        adj[Y].erase(find(all(adj[Y]), X)); DFS1(Y); low[X] = min(low[X], low[Y]);

        if (low[Y] > in[X]) bridges[{X, Y}] = bridges[{Y, X}] = true;
    }
}
void genComp(int X, int label) {
    comp[X] = label; EACH(Y, adj[X]) if (!comp[Y] && !bridges[{X, Y}]) genComp(Y, label);
}

void DFS2(int X, int P) {
    vis2[X] = true; EACH(Y, compAdj[X]) if (Y != P) { depth[Y] = depth[X] + 1; DFS2(Y, X); val[X] += val[Y]; }
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);

    cin >> N >> M; F0R(i, M) { int A, B; cin >> A >> B; adj[A].pb(B), adj[B].pb(A); edges.pb({A, B}); }

    FOR(i, 1, N + 1) if (!vis1[i]) DFS1(i); FOR(i, 1, N + 1) if (!comp[i]) genComp(i, nComp++);

    EACH(P, edges) if (bridges[{P.f, P.s}]) {
        int A = comp[P.f], B = comp[P.s]; compAdj[A].pb(B), compAdj[B].pb(A);
    }
    cin >> P; F0R(i, P) {
        int A, B; cin >> A >> B; val[comp[A]]++, val[comp[B]]--;
    }
    FOR(i, 1, nComp) if (!vis2[i]) DFS2(i, 0);

    F0R(i, M) { pi E = edges[i];
        if (!bridges[{E.f, E.s}]) { cout << "B"; continue; }

        int A = comp[E.f], B = comp[E.s]; int LOW = depth[A] > depth[B] ? A : B;

        if (val[LOW] == 0) { cout << "B"; continue; }

        int cnt = 0; if (depth[A] > depth[B]) cnt++; if (val[LOW] > 0) cnt++;

        if (cnt % 2) cout << "L"; else cout << "R";
    }
}

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