結果

問題 No.2301 Namorientation
コンテスト
ユーザー dyktr_06
提出日時 2023-05-12 22:00:07
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 1,162 ms / 3,000 ms
コード長 6,349 bytes
コンパイル時間 4,965 ms
コンパイル使用メモリ 281,320 KB
最終ジャッジ日時 2025-02-12 22:46:00
ジャッジサーバーID
（参考情報） 		judge3 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 30
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using namespace atcoder;

#define overload4(_1, _2, _3, _4, name, ...) name
#define rep1(n) for(int i = 0; i < (int)(n); ++i)
#define rep2(i, n) for(int i = 0; i < (int)(n); ++i)
#define rep3(i, a, b) for(int i = (a); i < (int)(b); ++i)
#define rep4(i, a, b, c) for(int i = (a); i < (int)(b); i += (c))
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)

#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; --i)
#define ALL(a) a.begin(), a.end()
#define Sort(a) sort(a.begin(), a.end())
#define RSort(a) sort(a.rbegin(), a.rend())

typedef long long int ll;
typedef unsigned long long ul;
typedef long double ld;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef vector<char> vc;
typedef vector<string> vst;
typedef vector<double> vd;
typedef vector<long double> vld;
typedef pair<long long, long long> P;

template<class T> long long sum(const T& a){ return accumulate(a.begin(), a.end(), 0LL); }
template<class T> auto min(const T& a){ return *min_element(a.begin(), a.end()); }
template<class T> auto max(const T& a){ return *max_element(a.begin(), a.end()); }

const long long MINF = 0x7fffffffffff;
const long long INF = 0x1fffffffffffffff;
const long long MOD = 998244353;
const long double EPS = 1e-9;
const long double PI = acos(-1);
 
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

template<typename T1, typename T2> istream &operator>>(istream &is, pair<T1, T2> &p){ is >> p.first >> p.second; return is; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){ os << "(" << p.first << ", " << p.second << ")"; return os; }
template<typename T> istream &operator>>(istream &is, vector<T> &v){ for(T &in : v) is >> in; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &v){ for(int i = 0; i < (int) v.size(); ++i){ os << v[i] << (i + 1 != (int) v.size() ? " " : ""); } return os; }
template <typename T, typename S> ostream &operator<<(ostream &os, const map<T, S> &mp){ for(auto &[key, val] : mp){ os << key << ":" << val << " "; } return os; }
template <typename T> ostream &operator<<(ostream &os, const set<T> &st){ auto itr = st.begin(); for(int i = 0; i < (int)st.size(); ++i){ os << *itr << (i + 1 != (int)st.size() ? " " : ""); itr++; } return os; }
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &st){ auto itr = st.begin(); for(int i = 0; i < (int)st.size(); ++i){ os << *itr << (i + 1 != (int)st.size() ? " " : ""); itr++; } return os; }
template <typename T> ostream &operator<<(ostream &os, queue<T> q){ while(q.size()){ os << q.front() << " "; q.pop(); } return os; }
template <typename T> ostream &operator<<(ostream &os, deque<T> q){ while(q.size()){ os << q.front() << " "; q.pop_front(); } return os; }
template <typename T> ostream &operator<<(ostream &os, stack<T> st){ while(st.size()){ os << st.top() << " "; st.pop(); } return os; }
template <class T, class Container, class Compare> ostream &operator<<(ostream &os, priority_queue<T, Container, Compare> pq){ while(pq.size()){ os << pq.top() << " "; pq.pop(); } return os; }

template<class T, class U> inline T vin(T& vec, U n) { vec.resize(n); for(int i = 0; i < (int) n; ++i) cin >> vec[i]; return vec; }
template<class T> inline void vout(T vec, string s = "\n"){ for(auto x : vec) cout << x << s; }
template<class... T> void in(T&... a){ (cin >> ... >> a); }
void out(){ cout << '\n'; }
template<class T, class... Ts> void out(const T& a, const Ts&... b){ cout << a; (cout << ... << (cout << ' ', b)); cout << '\n'; }
template<class T, class U> void inGraph(vector<vector<T>>& G, U n, U m, bool directed = false){ G.resize(n); for(int i = 0; i < m; ++i){ int a, b; cin >> a >> b; a--, b--; G[a].push_back(b); if(!directed) G[b].push_back(a); } }

/// https://ei1333.github.io/algorithm/namori.html
template< typename G >
struct Namori
{
  const G &g;
  vector< int > in;

  Namori(const G &g) : g(g), in(g.size(), 0) {}

  void decomposition(vector< int > &loop, vector< vector< int > > &forest)
  {
    int N = (int) in.size();
    for(int i = 0; i < N; i++) {
      in[i] = g[i].size();
    }
    forest.resize(N);
    queue< int > que;
    vector< bool > v(N, 0);
    for(int i = 0; i < N; i++) {
      if(in[i] == 1) {
        que.emplace(i);
        v[i] = true;
      }
    }
    while(!que.empty()) {
      int idx = que.front();
      que.pop();
      for(auto &to : g[idx]) {
        if(v[to]) continue;
        --in[to];
        forest[to].push_back(idx);
        forest[idx].push_back(to);
        if(in[to] > 1) continue;
        que.emplace(to);
        v[to] = true;
      }
    }

    function< void(int) > dfs = [&](int idx)
    {
      loop.push_back(idx);
      for(auto &to : g[idx]) {
        if(v[to]) continue;
        v[to] = true;
        dfs(to);
      }
    };
    for(int i = 0; i < N; i++) {
      if(v[i]) continue;
      v[i] = true;
      dfs(i);
      break;
    }
  }
};


ll n;


void input(){
    in(n);
}

void solve(){
    vector<vll> G(n);
    map<ll, map<ll, ll>> mp;
    rep(i, n){
        ll a, b; in(a, b); a--; b--;
        mp[a][b] = i;
        mp[b][a] = -1;
        G[a].push_back(b);
        G[b].push_back(a);
    }
    Namori<vector<vll>> nm(G);
    vi loop;
    vector<vi> forest;
    nm.decomposition(loop, forest);

    vst ans(n);
    ll m = loop.size();
    rep(i, m){
        ll k = mp[loop[i]][loop[(i + 1) % m]];
        if(k == -1){
            ans[mp[loop[(i + 1) % m]][loop[i]]] = "->";
        }else{
            ans[k] = "<-";
        }
    }
    vll check(n);
    queue<ll> q;
    rep(i, m){
        q.push(loop[i]);
        check[loop[i]] = 1;
    }
    while(q.size()){
        ll f = q.front(); q.pop();
        for(auto x : G[f]){
            if(check[x]) continue;
            check[x] = 1;
            ll k = mp[f][x];
            if(k == -1){
                ans[mp[x][f]] = "->";
            }else{
                ans[k] = "<-";
            }
            q.push(x);
        }
    }
    vout(ans, "\n");
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(20);
    
    input();
    solve();
}
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