結果

問題 No.2301 Namorientation
ユーザー rniya
提出日時 2023-05-12 21:38:42
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 159 ms / 3,000 ms
コード長 4,102 bytes
コンパイル時間 2,257 ms
コンパイル使用メモリ 209,520 KB
最終ジャッジ日時 2025-02-12 22:17:48
ジャッジサーバーID
（参考情報） 		judge1 / 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 #
プレゼンテーションモードにする

#include <bits/stdc++.h>
#ifdef LOCAL
#include <debug.hpp>
#else
#define debug(...) void(0)
#endif
template <bool directed> struct CycleDetection {
    std::vector<std::vector<int>> G;
    int n, pos;
    CycleDetection(int n) : G(n), n(n), pos(-1), seen(n, 0), finished(n, 0) {}
    void add_edge(int u, int v) {
        G[u].emplace_back(v);
        if (!directed) G[v].emplace_back(u);
    }
    std::vector<int> build() {
        for (int v = 0; v < n; v++) {
            if (!seen[v]) dfs(v, -1);
            if (~pos) break;
        }
        std::vector<int> res;
        while (!hist.empty()) {
            int t = hist.top();
            hist.pop();
            res.emplace_back(t);
            if (t == pos) break;
        }
        return res;
    }
  private:
    std::vector<int> seen, finished;
    std::stack<int> hist;
    void dfs(int v, int p) {
        seen[v] = 1;
        hist.emplace(v);
        for (int u : G[v]) {
            if (!directed and u == p) continue;
            if (finished[u]) continue;
            if (seen[u] and !finished[u]) {
                pos = u;
                return;
            }
            dfs(u, v);
            if (~pos) return;
        }
        finished[v] = 1;
        hist.pop();
    }
};
using namespace std;
typedef long long ll;
#define all(x) begin(x), end(x)
constexpr int INF = (1 << 30) - 1;
constexpr long long IINF = (1LL << 60) - 1;
constexpr int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
template <class T> istream& operator>>(istream& is, vector<T>& v) {
    for (auto& x : v) is >> x;
    return is;
}
template <class T> ostream& operator<<(ostream& os, const vector<T>& v) {
    auto sep = "";
    for (const auto& x : v) os << exchange(sep, " ") << x;
    return os;
}
template <class T, class U = T> bool chmin(T& x, U&& y) { return y < x and (x = forward<U>(y), true); }
template <class T, class U = T> bool chmax(T& x, U&& y) { return x < y and (x = forward<U>(y), true); }
template <class T> void mkuni(vector<T>& v) {
    sort(begin(v), end(v));
    v.erase(unique(begin(v), end(v)), end(v));
}
template <class T> int lwb(const vector<T>& v, const T& x) { return lower_bound(begin(v), end(v), x) - begin(v); }
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N;
    cin >> N;
    vector<vector<pair<int, int>>> G(N);
    vector<int> A(N), B(N);
    for (int i = 0; i < N; i++) {
        cin >> A[i] >> B[i];
        A[i]--, B[i]--;
        G[A[i]].emplace_back(B[i], i);
        G[B[i]].emplace_back(A[i], i);
    }
    vector<int> c, contained(N, false);
    {
        vector<bool> seen(N, false), finished(N, false);
        stack<int> hist;
        int pos = -1;
        auto dfs = [&](auto self, int v, int p) -> void {
            seen[v] = 1;
            hist.emplace(v);
            for (auto [u, idx] : G[v]) {
                if (u == p) continue;
                if (finished[u]) continue;
                if (seen[u] and !finished[u]) {
                    pos = u;
                    return;
                }
                self(self, u, v);
                if (~pos) return;
            }
            finished[v] = 1;
            hist.pop();
        };
        dfs(dfs, 0, -1);
        while (!hist.empty()) {
            int t = hist.top();
            hist.pop();
            c.emplace_back(t);
            contained[t] = true;
            if (t == pos) break;
        }
    }
    int len = c.size();
    vector<int> ans(N, -1);
    for (int i = 0; i < len; i++) {
        int u = c[i], v = c[(i + 1) % len];
        for (auto [w, idx] : G[u]) {
            if (w == v) {
                ans[idx] = (A[idx] == u);
            }
        }
    }
    {
        auto dfs = [&](auto self, int v) -> void {
            contained[v] = true;
            for (auto [u, idx] : G[v]) {
                if (contained[u]) continue;
                ans[idx] = (A[idx] == v);
                self(self, u);
            }
        };
        for (int& u : c) dfs(dfs, u);
    }
    for (int i = 0; i < N; i++) cout << (ans[i] == 0 ? "->" : "<-") << '\n';
    return 0;
}
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