結果

問題 No.2301 Namorientation
コンテスト
ユーザー tokusakurai
提出日時 2023-05-12 21:42:21
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 187 ms / 3,000 ms
コード長 7,053 bytes
コンパイル時間 2,127 ms
コンパイル使用メモリ 214,596 KB
最終ジャッジ日時 2025-02-12 22:22:44
ジャッジサーバーID
（参考情報） 		judge5 / 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>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define per(i, n) for (int i = (n)-1; i >= 0; i--)
#define rep2(i, l, r) for (int i = (l); i < (r); i++)
#define per2(i, l, r) for (int i = (r)-1; i >= (l); i--)
#define each(e, v) for (auto &e : v)
#define MM << " " <<
#define pb push_back
#define eb emplace_back
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;

template <typename T>
using minheap = priority_queue<T, vector<T>, greater<T>>;

template <typename T>
using maxheap = priority_queue<T>;

template <typename T>
bool chmax(T &x, const T &y) {
    return (x < y) ? (x = y, true) : false;
}

template <typename T>
bool chmin(T &x, const T &y) {
    return (x > y) ? (x = y, true) : false;
}

template <typename T>
int flg(T x, int i) {
    return (x >> i) & 1;
}

int popcount(int x) { return __builtin_popcount(x); }
int popcount(ll x) { return __builtin_popcountll(x); }
int topbit(int x) { return (x == 0 ? -1 : 31 - __builtin_clz(x)); }
int topbit(ll x) { return (x == 0 ? -1 : 63 - __builtin_clzll(x)); }
int botbit(int x) { return (x == 0 ? -1 : __builtin_ctz(x)); }
int botbit(ll x) { return (x == 0 ? -1 : __builtin_ctzll(x)); }

template <typename T>
void print(const vector<T> &v, T x = 0) {
    int n = v.size();
    for (int i = 0; i < n; i++) cout << v[i] + x << (i == n - 1 ? '\n' : ' ');
    if (v.empty()) cout << '\n';
}

template <typename T>
void printn(const vector<T> &v, T x = 0) {
    int n = v.size();
    for (int i = 0; i < n; i++) cout << v[i] + x << '\n';
}

template <typename T>
int lb(const vector<T> &v, T x) {
    return lower_bound(begin(v), end(v), x) - begin(v);
}

template <typename T>
int ub(const vector<T> &v, T x) {
    return upper_bound(begin(v), end(v), x) - begin(v);
}

template <typename T>
void rearrange(vector<T> &v) {
    sort(begin(v), end(v));
    v.erase(unique(begin(v), end(v)), end(v));
}

template <typename T>
vector<int> id_sort(const vector<T> &v, bool greater = false) {
    int n = v.size();
    vector<int> ret(n);
    iota(begin(ret), end(ret), 0);
    sort(begin(ret), end(ret), [&](int i, int j) { return greater ? v[i] > v[j] : v[i] < v[j]; });
    return ret;
}

template <typename T>
void reorder(vector<T> &a, const vector<int> &ord) {
    int n = a.size();
    vector<T> b(n);
    for (int i = 0; i < n; i++) b[i] = a[ord[i]];
    swap(a, b);
}

template <typename T>
T floor(T x, T y) {
    assert(y != 0);
    if (y < 0) x = -x, y = -y;
    return (x >= 0 ? x / y : (x - y + 1) / y);
}

template <typename T>
T ceil(T x, T y) {
    assert(y != 0);
    if (y < 0) x = -x, y = -y;
    return (x >= 0 ? (x + y - 1) / y : x / y);
}

template <typename S, typename T>
pair<S, T> operator+(const pair<S, T> &p, const pair<S, T> &q) {
    return make_pair(p.first + q.first, p.second + q.second);
}

template <typename S, typename T>
pair<S, T> operator-(const pair<S, T> &p, const pair<S, T> &q) {
    return make_pair(p.first - q.first, p.second - q.second);
}

template <typename S, typename T>
istream &operator>>(istream &is, pair<S, T> &p) {
    S a;
    T b;
    is >> a >> b;
    p = make_pair(a, b);
    return is;
}

template <typename S, typename T>
ostream &operator<<(ostream &os, const pair<S, T> &p) {
    return os << p.first << ' ' << p.second;
}

struct io_setup {
    io_setup() {
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
    }
} io_setup;

const int inf = (1 << 30) - 1;
const ll INF = (1LL << 60) - 1;
// const int MOD = 1000000007;
const int MOD = 998244353;

template <bool directed = false>
struct Graph {
    struct edge {
        int to, id;
        edge(int to, int id) : to(to), id(id) {}
    };

    vector<vector<edge>> es;
    const int n;
    int m;

    vector<int> used;

    Graph(int n) : es(n), n(n), m(0), used(n) {}

    void add_edge(int from, int to) {
        es[from].emplace_back(to, m);
        if (!directed) es[to].emplace_back(from, m);
        m++;
    }

    bool detect_path(int now, int t, vector<int> &ret, bool use_id = false) {
        used[now] = true;
        if (now == t) {
            if (!use_id) ret.push_back(now);
            return true;
        }
        for (auto &e : es[now]) {
            if (used[e.to]) continue;
            if (detect_path(e.to, t, ret, use_id)) {
                ret.push_back(use_id ? e.id : now);
                return true;
            }
        }
        return false;
    }

    // 点素な s-t パスを 1 つ検出
    vector<int> find_path(int s, int t, bool use_id = false) {
        vector<int> ret;
        fill(begin(used), end(used), 0);
        detect_path(s, t, ret, use_id);
        reverse(begin(ret), end(ret));
        return ret;
    }

    int detect_cycle(int now, vector<int> &ret, int pre = -1, bool use_id = false) {
        if (used[now]++) return 1;
        for (auto &e : es[now]) {
            if (e.id == pre) continue;
            int k = detect_cycle(e.to, ret, e.id, use_id);
            if (k == 2) return 2;
            if (k == 1) {
                ret.push_back(use_id ? e.id : now);
                return used[now];
            }
        }
        return 0;
    }

    // 点素な閉路を 1 つ検出
    vector<int> find_cycle(bool use_id = false) {
        vector<int> ret;
        fill(begin(used), end(used), 0);
        for (int i = 0; i < n; i++) {
            if (used[i]) continue;
            detect_cycle(i, ret, -1, use_id);
            if (!ret.empty()) {
                reverse(begin(ret), end(ret));
                return ret;
            }
        }
        return {};
    }
};

void solve() {
    int N;
    cin >> N;

    Graph G(N);

    vector<int> u(N), v(N);
    vector<vector<int>> es(N);
    rep(i, N) {
        cin >> u[i] >> v[i];
        u[i]--, v[i]--;
        G.add_edge(u[i], v[i]);
        es[u[i]].eb(v[i]), es[v[i]].eb(u[i]);
    }

    auto c = G.find_cycle(true);
    auto c2 = G.find_cycle(false);
    set<pii> s;
    rep(i, sz(c2)) {
        s.emplace(c2[i], c2[(i + 1) % sz(c2)]); //
    }

    vector<int> ans(N, -1);
    vector<int> used(N, false);
    each(e, c) {
        ans[e] = (s.count(pii(u[e], v[e])) ? 0 : 1);
        used[u[e]] = true, used[v[e]] = true;
    }

    vector<int> par(N, -1);

    auto dfs = [&](auto &&dfs, int now, int pre = -1) -> void {
        each(e, es[now]) {
            if (used[e] || e == pre) continue;
            par[e] = now;
            dfs(dfs, e, now);
        }
    };

    rep(i, N) {
        if (!used[i]) continue;
        dfs(dfs, i, -1);
    }

    rep(i, N) {
        if (ans[i] == -1) {
            if (par[u[i]] == v[i]) {
                ans[i] = 0;
            } else {
                ans[i] = 1;
            }
        }
    }

    rep(i, N) cout << (ans[i] == 0 ? "->\n" : "<-\n");
}

int main() {
    int T = 1;
    // cin >> T;
    while (T--) solve();
}
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