제출 #266456

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
266456		MarcoMeijer	One-Way Streets (CEOI17_oneway)	C++14	100 / 100	1195 ms	101384 KiB

oneway

#include <bits/stdc++.h>
using namespace std;

// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e9
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
#define sz size()
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

// input
template<class T> void IN(T& x) {cin >> x;}
template<class H, class... T> void IN(H& h, T&... t) {IN(h); IN(t...); }

// output
template<class T1, class T2> void OUT(const pair<T1,T2>& x);
template<class T> void OUT(const T& x) {cout << x;}
template<class H, class... T> void OUT(const H& h, const T&... t) {OUT(h); OUT(t...); }
template<class T1, class T2> void OUT(const pair<T1,T2>& x) {OUT(x.fi,' ',x.se);}
template<class... T> void OUTL(const T&... t) {OUT(t..., "\n"); }
template<class H> void OUTLS(const H& h) {OUTL(h); }
template<class H, class... T> void OUTLS(const H& h, const T&... t) {OUT(h,' '); OUTLS(t...); }

//===================//
//  Added libraries  //
//===================//

//===================//
//end added libraries//
//===================//

void program();
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    program();
}


//===================//
//   begin program   //
//===================//

const int MX = 3e5;

int n, m, p;
int a[MX], b[MX], x[MX], y[MX];
bitset<MX> visited, inside;
vi adj[MX];
vi dir[MX], rev[MX];
stack<int> stck;
int comp[MX], compN=0;
set<ii> adjComp[MX];
map<ii,int> adjCEW;
map<ii,int> pToEdge;
string ans;
map<ii,int> cnt;
int added[MX];

void dfsDir(int u, int p=-1) {
    if(visited[u]) return;
    visited[u] = 1;
    inside[u] = 1;
    FOR(v,adj[u]) if(v != p) {
        if(!visited[v] || inside[v]) {
            dir[u].pb(v);
            rev[v].pb(u);
            if(cnt[{u,v}] >= 2) {
                dir[v].pb(u);
                rev[u].pb(v);
            }
        }
        if(!visited[v]) dfsDir(v, u);
    }
    inside[u] = 0;
}
void dfsSCC1(int u) {
    if(visited[u]) return;
    visited[u] = 1;
    FOR(v,dir[u]) dfsSCC1(v);
    stck.push(u);
}
void dfsSCC2(int u) {
    if(visited[u]) return;
    visited[u] = 1;
    FOR(v,rev[u]) dfsSCC2(v);
    comp[u] = compN;
}
void findSCC() {
    visited.reset();
    RE1(i,n) dfsSCC1(i);

    visited.reset();
    while(!stck.empty()) {
        int u = stck.top(); stck.pop();
        if(visited[u]) continue;
        dfsSCC2(u);
        compN++;
    }

    RE1(u,n) {
        FOR(v,adj[u]) {
            if(comp[u] != comp[v]) {
                adjComp[comp[u]].insert({comp[v],pToEdge[{u,v}]});
                adjComp[comp[v]].insert({comp[u],pToEdge[{u,v}]});
            }
        }
    }
}

int PC[MX];
void dfsPC(int u, int p=-1) {
    visited[u] = 1;
    PC[u] = p;
    FOR(v,adjComp[u]) if(v.fi != p) {
        dfsPC(v.fi,u);
    }
}

int SM[MX];
void dfsAns(int u, int p=-1) {
    SM[u] = 0;
    FOR(v,adjComp[u]) if(v.fi != p) {
        dfsAns(v.fi, u);
        int tot = SM[v.fi] + adjCEW[{u,v.fi}];
        SM[u] += tot;
        int e = v.se;
        if(tot != 0) ans[e] = 'R';
        if(tot > 0) {
            // v -> u
            if(comp[a[e]] != v.fi) ans[e] = 'L';
        }
        if(tot < 0) {
            // u -> v
            if(comp[a[e]] != u) ans[e] = 'L';
        }
    }
}

void program() {
    IN(n,m);
    RE(i,m) {
        int u, v;
        IN(u,v);
        adj[u].pb(v);
        adj[v].pb(u);
        a[i] = u;
        b[i] = v;
        pToEdge[{u,v}] = i;
        pToEdge[{v,u}] = i;
        cnt[{u,v}]++;
        cnt[{v,u}]++;
    }
    IN(p);
    RE(i,p) {
        IN(x[i],y[i]);
    }

    visited.reset();
    RE1(i,n) dfsDir(i);
    
    findSCC();

    ans.assign(m,'X');
    RE(i,m) ans[i] = 'B';

    visited.reset();
    vi roots;
    RE(i,compN) if(!visited[i]) {
        dfsPC(i);
        roots.pb(i);
    }
    RE(i,p) {
        int u=comp[x[i]], v=comp[y[i]];

        // u -> LCA
        adjCEW[{u,PC[u]}]++;
        adjCEW[{PC[u],u}]++;
        
        // LCA -> v
        adjCEW[{v,PC[v]}]--;
        adjCEW[{PC[v],v}]--;
    }
    FOR(i,roots) dfsAns(i);

    OUTL(ans);
}

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