結果

問題 No.1254 補強への架け橋
ユーザー gyouzasushi
提出日時 2024-05-31 16:08:54
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 443 ms / 2,000 ms
コード長 3,472 bytes
コンパイル時間 2,508 ms
コンパイル使用メモリ 208,832 KB
最終ジャッジ日時 2025-02-21 17:21:03
ジャッジサーバーID
（参考情報） 		judge2 / judge3
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 * 3
other AC * 123
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

#line 1 "main.cpp"
#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rrep(i, n) for (int i = (int)(n - 1); i >= 0; i--)
#define all(x) (x).begin(), (x).end()
#define sz(x) int(x.size())
using namespace std;
using ll = long long;
constexpr int INF = 1e9;
constexpr ll LINF = 1e18;
string YesNo(bool cond) {
    return cond ? "Yes" : "No";
}
string YESNO(bool cond) {
    return cond ? "YES" : "NO";
}
template <class T>
bool chmax(T& a, const T& b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template <class T>
bool chmin(T& a, const T& b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}
template <typename T, class F>
T bisect(T ok, T ng, const F& f) {
    while (abs(ok - ng) > 1) {
        T mid = min(ok, ng) + (abs(ok - ng) >> 1);
        (f(mid) ? ok : ng) = mid;
    }
    return ok;
}
template <typename T, class F>
T bisect_double(T ok, T ng, const F& f, int iter = 100) {
    while (iter--) {
        T mid = (ok + ng) / 2;
        (f(mid) ? ok : ng) = mid;
    }
    return ok;
}
template <class T>
vector<T> make_vec(size_t a) {
    return vector<T>(a);
}
template <class T, class... Ts>
auto make_vec(size_t a, Ts... ts) {
    return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}
template <typename T>
istream& operator>>(istream& is, vector<T>& v) {
    for (int i = 0; i < int(v.size()); i++) {
        is >> v[i];
    }
    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];
        if (i < sz(v) - 1) os << ' ';
    }
    return os;
}
#line 2 "/Users/gyouzasushi/kyopro/library/graph/functional_graph.hpp"
#line 5 "/Users/gyouzasushi/kyopro/library/graph/functional_graph.hpp"
struct functional_graph {
public:
    functional_graph(int n) : _n(n), graph(n) {
    }
    void add_edge(int u, int v) {
        graph[u].push_back(v);
        graph[v].push_back(u);
    }
    void add_directed_edge(int from, int to) {
        graph[from].push_back(to);
    }
    std::vector<int> loop() {
        std::vector<int> path;
        std::vector<int> check(_n, 0);
        auto dfs = [&](auto dfs, int u, int p) -> int {
            check[u]++;
            path.push_back(u);
            for (int v : graph[u]) {
                if (v == p) continue;
                if (check[v] == 0) {
                    int ret = dfs(dfs, v, u);
                    if (ret != -1) return ret;
                } else if (check[v] == 1) {
                    return v;
                }
            }
            path.pop_back();
            check[u]++;
            return -1;
        };
        std::vector<int>::iterator it =
            std::find(path.begin(), path.end(), dfs(dfs, 0, -1));
        return std::vector(it, path.end());
    }
    std::vector<std::vector<std::vector<int>>> tree() {
        return {};
    }
private:
    int _n;
    std::vector<std::vector<int>> graph;
};
#line 73 "main.cpp"
int main() {
    int n;
    cin >> n;
    functional_graph g(n);
    map<pair<int, int>, int> id;
    rep(i, n) {
        int a, b;
        cin >> a >> b;
        g.add_edge(--a, --b);
        id[{a, b}] = id[{b, a}] = i;
    }
    vector loop = g.loop();
    int k = sz(loop);
    cout << k << '\n';
    rep(i, k) {
        int u = loop[i];
        int v = loop[(i + 1) % k];
        cout << id[{u, v}] + 1 << " \n"[i == k - 1];
    }
}
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