結果

問題 No.1254 補強への架け橋
ユーザー hitonanodehitonanode
提出日時 2020-10-16 20:17:05
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 114 ms / 2,000 ms
コード長 8,095 bytes
コンパイル時間 2,466 ms
コンパイル使用メモリ 213,268 KB
実行使用メモリ 22,644 KB
最終ジャッジ日時 2024-07-20 21:06:03
合計ジャッジ時間 14,216 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge1
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
5,248 KB
testcase_01 AC 2 ms
5,376 KB
testcase_02 AC 2 ms
5,376 KB
testcase_03 AC 2 ms
5,376 KB
testcase_04 AC 2 ms
5,376 KB
testcase_05 AC 2 ms
5,376 KB
testcase_06 AC 2 ms
5,376 KB
testcase_07 AC 2 ms
5,376 KB
testcase_08 AC 2 ms
5,376 KB
testcase_09 AC 3 ms
5,376 KB
testcase_10 AC 2 ms
5,376 KB
testcase_11 AC 3 ms
5,376 KB
testcase_12 AC 3 ms
5,376 KB
testcase_13 AC 3 ms
5,376 KB
testcase_14 AC 2 ms
5,376 KB
testcase_15 AC 2 ms
5,376 KB
testcase_16 AC 3 ms
5,376 KB
testcase_17 AC 2 ms
5,376 KB
testcase_18 AC 3 ms
5,376 KB
testcase_19 AC 2 ms
5,376 KB
testcase_20 AC 2 ms
5,376 KB
testcase_21 AC 2 ms
5,376 KB
testcase_22 AC 2 ms
5,376 KB
testcase_23 AC 2 ms
5,376 KB
testcase_24 AC 2 ms
5,376 KB
testcase_25 AC 2 ms
5,376 KB
testcase_26 AC 2 ms
5,376 KB
testcase_27 AC 3 ms
5,376 KB
testcase_28 AC 2 ms
5,376 KB
testcase_29 AC 2 ms
5,376 KB
testcase_30 AC 2 ms
5,376 KB
testcase_31 AC 3 ms
5,376 KB
testcase_32 AC 2 ms
5,376 KB
testcase_33 AC 2 ms
5,376 KB
testcase_34 AC 2 ms
5,376 KB
testcase_35 AC 2 ms
5,376 KB
testcase_36 AC 2 ms
5,376 KB
testcase_37 AC 2 ms
5,376 KB
testcase_38 AC 2 ms
5,376 KB
testcase_39 AC 2 ms
5,376 KB
testcase_40 AC 2 ms
5,376 KB
testcase_41 AC 2 ms
5,376 KB
testcase_42 AC 2 ms
5,376 KB
testcase_43 AC 2 ms
5,376 KB
testcase_44 AC 2 ms
5,376 KB
testcase_45 AC 3 ms
5,376 KB
testcase_46 AC 2 ms
5,376 KB
testcase_47 AC 2 ms
5,376 KB
testcase_48 AC 2 ms
5,376 KB
testcase_49 AC 2 ms
5,376 KB
testcase_50 AC 2 ms
5,376 KB
testcase_51 AC 3 ms
5,376 KB
testcase_52 AC 2 ms
5,376 KB
testcase_53 AC 2 ms
5,376 KB
testcase_54 AC 2 ms
5,376 KB
testcase_55 AC 2 ms
5,376 KB
testcase_56 AC 2 ms
5,376 KB
testcase_57 AC 2 ms
5,376 KB
testcase_58 AC 2 ms
5,376 KB
testcase_59 AC 2 ms
5,376 KB
testcase_60 AC 2 ms
5,376 KB
testcase_61 AC 2 ms
5,376 KB
testcase_62 AC 2 ms
5,376 KB
testcase_63 AC 7 ms
5,376 KB
testcase_64 AC 3 ms
5,376 KB
testcase_65 AC 5 ms
5,376 KB
testcase_66 AC 4 ms
5,376 KB
testcase_67 AC 3 ms
5,376 KB
testcase_68 AC 5 ms
5,376 KB
testcase_69 AC 5 ms
5,376 KB
testcase_70 AC 4 ms
5,376 KB
testcase_71 AC 3 ms
5,376 KB
testcase_72 AC 5 ms
5,376 KB
testcase_73 AC 3 ms
5,376 KB
testcase_74 AC 5 ms
5,376 KB
testcase_75 AC 5 ms
5,376 KB
testcase_76 AC 2 ms
5,376 KB
testcase_77 AC 4 ms
5,376 KB
testcase_78 AC 6 ms
5,376 KB
testcase_79 AC 6 ms
6,944 KB
testcase_80 AC 6 ms
6,944 KB
testcase_81 AC 6 ms
6,944 KB
testcase_82 AC 6 ms
6,940 KB
testcase_83 AC 66 ms
11,984 KB
testcase_84 AC 61 ms
11,736 KB
testcase_85 AC 35 ms
8,528 KB
testcase_86 AC 52 ms
10,720 KB
testcase_87 AC 72 ms
11,420 KB
testcase_88 AC 9 ms
6,940 KB
testcase_89 AC 79 ms
11,828 KB
testcase_90 AC 39 ms
8,648 KB
testcase_91 AC 33 ms
7,628 KB
testcase_92 AC 15 ms
6,940 KB
testcase_93 AC 53 ms
10,408 KB
testcase_94 AC 47 ms
9,976 KB
testcase_95 AC 50 ms
9,964 KB
testcase_96 AC 70 ms
11,608 KB
testcase_97 AC 27 ms
7,112 KB
testcase_98 AC 72 ms
11,544 KB
testcase_99 AC 35 ms
8,308 KB
testcase_100 AC 80 ms
12,196 KB
testcase_101 AC 14 ms
6,940 KB
testcase_102 AC 8 ms
6,940 KB
testcase_103 AC 16 ms
6,944 KB
testcase_104 AC 21 ms
6,944 KB
testcase_105 AC 58 ms
10,284 KB
testcase_106 AC 27 ms
7,484 KB
testcase_107 AC 68 ms
11,948 KB
testcase_108 AC 66 ms
11,900 KB
testcase_109 AC 48 ms
10,372 KB
testcase_110 AC 46 ms
9,756 KB
testcase_111 AC 44 ms
10,140 KB
testcase_112 AC 19 ms
6,940 KB
testcase_113 AC 39 ms
9,120 KB
testcase_114 AC 25 ms
7,304 KB
testcase_115 AC 9 ms
6,940 KB
testcase_116 AC 30 ms
7,968 KB
testcase_117 AC 20 ms
6,940 KB
testcase_118 AC 70 ms
11,464 KB
testcase_119 AC 34 ms
8,264 KB
testcase_120 AC 59 ms
11,088 KB
testcase_121 AC 17 ms
6,940 KB
testcase_122 AC 29 ms
7,796 KB
testcase_123 AC 2 ms
6,944 KB
testcase_124 AC 108 ms
22,644 KB
testcase_125 AC 114 ms
22,508 KB
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;
using lint = long long;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template <typename T, typename V>
void ndarray(vector<T>& vec, const V& val, int len) { vec.assign(len, val); }
template <typename T, typename V, typename... Args> void ndarray(vector<T>& vec, const V& val, int len, Args... args) { vec.resize(len), for_each(begin(vec), end(vec), [&](T& v) { ndarray(v, val, args...); }); }
template <typename T> bool chmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template <typename T> bool chmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; }
template <typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template <typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
template <typename T> vector<T> srtunq(vector<T> vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; }
template <typename T> istream &operator>>(istream &is, vector<T> &vec) { for (auto &v : vec) is >> v; return is; }
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; }
#if __cplusplus >= 201703L
template <typename... T> istream &operator>>(istream &is, tuple<T...> &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; }
template <typename... T> ostream &operator<<(ostream &os, const tuple<T...> &tpl) { std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os; }
#endif
template <typename T> ostream &operator<<(ostream &os, const deque<T> &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <typename T> ostream &operator<<(ostream &os, const set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T, typename TH> ostream &operator<<(ostream &os, const unordered_set<T, TH> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa) { os << '(' << pa.first << ',' << pa.second << ')'; return os; }
template <typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
template <typename TK, typename TV, typename TH> ostream &operator<<(ostream &os, const unordered_map<TK, TV, TH> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
#ifdef HITONANODE_LOCAL
#define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl
#else
#define dbg(x) {}
#endif

struct UndirectedGraph
{
    int V; // # of vertices
    int E; // # of edges
    int k;
    std::vector<std::vector<std::pair<int, int>>> to;
    std::vector<std::pair<int, int>> edges;
    std::vector<int> root_ids; // DFS forestの構築で根になった頂点

    std::vector<int> is_bridge; // Whether edge i is bridge or not, size = E
    std::vector<int> is_articulation; // whether vertex i is articulation point or not, size = V

    // lowlink
    std::vector<int> order;   // visiting order of DFS tree, size = V
    std::vector<int> lowlink; // size = V
    std::vector<int> is_dfstree_edge; // size = E

    int tecc_num; // 二重辺連結成分数
    std::vector<int> tecc_id; // 各頂点が何個目の二重辺連結成分か

    int tvcc_num; // 二重頂点連結成分数
    std::vector<int> tvcc_id; // 各辺が何個目の二重頂点連結成分か

    UndirectedGraph(int V) : V(V), E(0), k(0), to(V), is_articulation(V, 0), order(V, -1), lowlink(V, -1), tecc_num(0), tvcc_num(0) {}

    void add_edge(int v1, int v2)
    {
        assert(v1 >= 0 and v1 < V);
        assert(v2 >= 0 and v2 < V);
        to[v1].emplace_back(v2, E);
        to[v2].emplace_back(v1, E);
        edges.emplace_back(v1, v2);
        is_bridge.push_back(0);
        is_dfstree_edge.push_back(0);
        tvcc_id.push_back(-1);
        E++;
    }

    std::vector<int> _edge_stack;
    int _root_now;

    // Build DFS tree
    // Complexity: O(V + E)
    void dfs_lowlink(int now, int prv_eid = -1)
    {
        if (prv_eid < 0) _root_now = k;
        if (prv_eid == -1) root_ids.push_back(now);
        order[now] = lowlink[now] = k++;
        for (const auto &nxt : to[now]) if (nxt.second != prv_eid)
        {
            if (order[nxt.first] < order[now]) _edge_stack.push_back(nxt.second);
            if (order[nxt.first] >= 0)
            {
                lowlink[now] = std::min(lowlink[now], order[nxt.first]);
            }
            else
            {
                is_dfstree_edge[nxt.second] = 1;
                dfs_lowlink(nxt.first, nxt.second);
                lowlink[now] = std::min(lowlink[now], lowlink[nxt.first]);

                if ((order[now] == _root_now and order[nxt.first] != _root_now + 1) or (order[now] != _root_now and lowlink[nxt.first] >= order[now])) {
                    is_articulation[now] = 1;
                }
                if (lowlink[nxt.first] >= order[now]) {
                    while (true) {
                        int e = _edge_stack.back();
                        tvcc_id[e] = tvcc_num;
                        _edge_stack.pop_back();
                        if (std::minmax(edges[e].first, edges[e].second) == std::minmax(now, nxt.first)) {
                            break;
                        }
                    }
                    tvcc_num++;
                }
            }
        }
    }

    // Find all bridges
    // Complexity: O(V + E)
    void detectBridge()
    {
        for (int i = 0; i < E; i++)
        {
            int v1 = edges[i].first, v2 = edges[i].second;
            if (order[v1] < 0) dfs_lowlink(v1);
            if (order[v1] > order[v2]) std::swap(v1, v2);
            if (order[v1] < lowlink[v2]) is_bridge[i] = 1;
        }
    }

    // Find two-edge-connected components and classify all vertices
    // Complexity:  O(V + E)
    void two_edge_connected_components()
    {
        tecc_num = 0;
        tecc_id.assign(V, -1);

        for (int i = 0; i < V; i++) if (tecc_id[i] == -1)
        {
            tecc_id[i] = tecc_num;
            std::queue<int> que;
            que.push(i);
            while (!que.empty())
            {
                int now = que.front();
                que.pop();
                for (const auto &edge : to[now])
                {
                    int nxt = edge.first;
                    if (tecc_id[nxt] >= 0 or is_bridge[edge.second]) continue;
                    tecc_id[nxt] = tecc_num;
                    que.push(nxt);
                }
            }
            tecc_num++;
        }
    }
};

int main()
{
    int N;
    cin >> N;
    UndirectedGraph graph(N);
    REP(i, N) {
        int a, b;
        cin >> a >> b;
        graph.add_edge(a - 1, b - 1);
    }
    graph.detectBridge();
    vector<int> ret;
    REP(i, N) if (!graph.is_bridge[i]) ret.emplace_back(i + 1);
    cout << ret.size() << '\n';
    for (auto x : ret) cout << x << ' ';
    cout << '\n';
}
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