test/verify/yukicoder-1254.test.cpp

• View this file on GitHub
• Last update: 2026-08-10 14:57:04+00:00
• Problem: https://yukicoder.me/problems/no/1254

Depends on

• Graph Template (グラフテンプレート) (graph/graph-template.hpp)
• Namori Graph (graph/others/namori-graph.hpp)

Code

// competitive-verifier: PROBLEM https://yukicoder.me/problems/no/1254

#include <algorithm>
#include <iostream>
#include <vector>

#include "../../graph/others/namori-graph.hpp"

using namespace std;

int main() {
  int N;
  cin >> N;
  NamoriGraph<int> g(N);
  g.read(N);
  g.build();
  vector<int> ans;
  for (auto& e : g.loop_edges) {
    ans.emplace_back(e.idx + 1);
  }
  sort(begin(ans), end(ans));
  cout << ans.size() << "\n";
  for (int i = 0; i < static_cast<int>(ans.size()); ++i) {
    if (i) cout << ' ';
    cout << ans[i];
  }
  cout << '\n';
}

#line 1 "test/verify/yukicoder-1254.test.cpp"
// competitive-verifier: PROBLEM https://yukicoder.me/problems/no/1254

#include <algorithm>
#include <iostream>
#include <vector>

#line 2 "graph/others/namori-graph.hpp"

#line 4 "graph/others/namori-graph.hpp"
#include <queue>
#line 6 "graph/others/namori-graph.hpp"

#line 2 "graph/graph-template.hpp"

#include <cstddef>
#line 6 "graph/graph-template.hpp"

template <typename T = int>
struct Edge {
  int from, to;
  T cost;
  int idx;

  Edge() = default;

  Edge(int from, int to, T cost = 1, int idx = -1)
      : from(from), to(to), cost(cost), idx(idx) {}

  operator int() const { return to; }
};

template <typename T = int>
struct Graph {
  std::vector<std::vector<Edge<T> > > g;
  int es;

  Graph() = default;

  explicit Graph(int n) : g(n), es(0) {}

  std::size_t size() const { return g.size(); }

  void add_directed_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es++);
  }

  void add_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es);
    g[to].emplace_back(to, from, cost, es++);
  }

  void read(int M, int padding = -1, bool weighted = false,
            bool directed = false) {
    for (int i = 0; i < M; i++) {
      int a, b;
      std::cin >> a >> b;
      a += padding;
      b += padding;
      T c = T(1);
      if (weighted) std::cin >> c;
      if (directed)
        add_directed_edge(a, b, c);
      else
        add_edge(a, b, c);
    }
  }

  inline std::vector<Edge<T> >& operator[](const int& k) { return g[k]; }

  inline const std::vector<Edge<T> >& operator[](const int& k) const {
    return g[k];
  }
};

template <typename T = int>
using Edges = std::vector<Edge<T> >;
#line 8 "graph/others/namori-graph.hpp"

/**
 * @brief Namori Graph
 *
 */
template <typename T = int>
struct NamoriGraph : Graph<T> {
 public:
  using Graph<T>::Graph;
  using Graph<T>::g;

  std::vector<Graph<T> > forest;
  Edges<T> loop_edges;

  struct Info {
    int tree_id, id;
  };

  Info operator[](const int& k) const { return (Info){mark_id[k], id[k]}; }

  int inv(int tree_id, int k) { return iv[tree_id][k]; }

  void build() {
    int n = (int)g.size();
    std::vector<int> deg(n), used(n);
    std::queue<int> que;
    for (int i = 0; i < n; i++) {
      deg[i] = (int)g[i].size();
      if (deg[i] == 1) {
        que.emplace(i);
        used[i] = true;
      }
    }
    while (not que.empty()) {
      int idx = que.front();
      que.pop();
      for (auto& e : g[idx]) {
        if (used[e.to]) {
          continue;
        }
        --deg[e.to];
        if (deg[e.to] == 1) {
          que.emplace(e.to);
          used[e.to] = true;
        }
      }
    }
    int mx = 0;
    for (auto& edges : g) {
      for (auto& e : edges) mx = std::max(mx, e.idx);
    }
    std::vector<int> edge_used(mx + 1);
    std::vector<int> loop;
    for (int v = 0; v < n; v++) {
      if (!used[v]) {
        for (bool update = true; update;) {
          update = false;
          loop.emplace_back(v);
          for (auto& e : g[v]) {
            if (used[e.to] or edge_used[e.idx]) {
              continue;
            }
            edge_used[e.idx] = true;
            loop_edges.emplace_back(v, e.to, e.cost, e.idx);
            v = e.to;
            update = true;
            break;
          }
        }
        break;
      }
    }
    loop.pop_back();
    mark_id.resize(n);
    id.resize(n);
    for (int i = 0; i < (int)loop.size(); i++) {
      int pre = loop[(i + loop.size() - 1) % loop.size()];
      int nxt = loop[(i + 1) % loop.size()];
      int sz = 0;
      mark_id[loop[i]] = i;
      iv.emplace_back();
      id[loop[i]] = sz++;
      iv.back().emplace_back(loop[i]);
      for (auto& e : g[loop[i]]) {
        if (e.to != pre and e.to != nxt) {
          mark_dfs(e.to, loop[i], i, sz);
        }
      }
      Graph<T> tree(sz);
      for (auto& e : g[loop[i]]) {
        if (e.to != pre and e.to != nxt) {
          tree.g[id[loop[i]]].emplace_back(id[loop[i]], id[e.to], e.cost,
                                           e.idx);
          tree.g[id[e.to]].emplace_back(id[e.to], id[loop[i]], e.cost, e.idx);
          build_dfs(e.to, loop[i], tree);
        }
      }
      forest.emplace_back(tree);
    }
  }

 private:
  std::vector<std::vector<int> > iv;
  std::vector<int> mark_id, id;

  void mark_dfs(int idx, int par, int k, int& l) {
    mark_id[idx] = k;
    id[idx] = l++;
    iv.back().emplace_back(idx);
    for (auto& e : g[idx]) {
      if (e.to != par) {
        mark_dfs(e.to, idx, k, l);
      }
    }
  }

  void build_dfs(int idx, int par, Graph<T>& tree) {
    for (auto& e : g[idx]) {
      if (e.to != par) {
        tree.g[id[idx]].emplace_back(id[idx], id[e.to], e.cost, e.idx);
        tree.g[id[e.to]].emplace_back(id[e.to], id[idx], e.cost, e.idx);
        build_dfs(e.to, idx, tree);
      }
    }
  }
};
#line 8 "test/verify/yukicoder-1254.test.cpp"

using namespace std;

int main() {
  int N;
  cin >> N;
  NamoriGraph<int> g(N);
  g.read(N);
  g.build();
  vector<int> ans;
  for (auto& e : g.loop_edges) {
    ans.emplace_back(e.idx + 1);
  }
  sort(begin(ans), end(ans));
  cout << ans.size() << "\n";
  for (int i = 0; i < static_cast<int>(ans.size()); ++i) {
    if (i) cout << ' ';
    cout << ans[i];
  }
  cout << '\n';
}

Test cases

Env	Name	Status	Elapsed	Memory
g++	01_sample_01	AC	2 ms	4 MB
g++	01_sample_02	AC	2 ms	4 MB
g++	01_sample_03	AC	2 ms	3 MB
g++	02_Tiny_1	AC	2 ms	3 MB
g++	02_Tiny_10	AC	2 ms	4 MB
g++	02_Tiny_2	AC	2 ms	4 MB
g++	02_Tiny_3	AC	2 ms	4 MB
g++	02_Tiny_4	AC	2 ms	3 MB
g++	02_Tiny_5	AC	2 ms	4 MB
g++	02_Tiny_6	AC	2 ms	4 MB
g++	02_Tiny_7	AC	2 ms	4 MB
g++	02_Tiny_8	AC	2 ms	3 MB
g++	02_Tiny_9	AC	2 ms	4 MB
g++	03_Small1	AC	2 ms	4 MB
g++	03_Small10	AC	2 ms	4 MB
g++	03_Small11	AC	2 ms	4 MB
g++	03_Small12	AC	2 ms	4 MB
g++	03_Small13	AC	2 ms	4 MB
g++	03_Small14	AC	2 ms	4 MB
g++	03_Small15	AC	2 ms	3 MB
g++	03_Small2	AC	2 ms	4 MB
g++	03_Small3	AC	2 ms	4 MB
g++	03_Small4	AC	2 ms	4 MB
g++	03_Small5	AC	2 ms	4 MB
g++	03_Small6	AC	2 ms	3 MB
g++	03_Small7	AC	2 ms	4 MB
g++	03_Small8	AC	2 ms	4 MB
g++	03_Small9	AC	2 ms	4 MB
g++	03_Small_1	AC	2 ms	4 MB
g++	03_Small_10	AC	2 ms	4 MB
g++	03_Small_11	AC	2 ms	4 MB
g++	03_Small_12	AC	2 ms	3 MB
g++	03_Small_13	AC	2 ms	3 MB
g++	03_Small_14	AC	2 ms	4 MB
g++	03_Small_15	AC	2 ms	4 MB
g++	03_Small_2	AC	2 ms	4 MB
g++	03_Small_3	AC	2 ms	4 MB
g++	03_Small_4	AC	2 ms	4 MB
g++	03_Small_5	AC	2 ms	4 MB
g++	03_Small_6	AC	2 ms	4 MB
g++	03_Small_7	AC	2 ms	4 MB
g++	03_Small_8	AC	2 ms	4 MB
g++	03_Small_9	AC	2 ms	3 MB
g++	04_Medium_1	AC	2 ms	4 MB
g++	04_Medium_10	AC	2 ms	4 MB
g++	04_Medium_11	AC	2 ms	4 MB
g++	04_Medium_12	AC	2 ms	4 MB
g++	04_Medium_13	AC	2 ms	4 MB
g++	04_Medium_14	AC	2 ms	4 MB
g++	04_Medium_15	AC	2 ms	4 MB
g++	04_Medium_16	AC	2 ms	4 MB
g++	04_Medium_17	AC	2 ms	4 MB
g++	04_Medium_18	AC	2 ms	4 MB
g++	04_Medium_19	AC	2 ms	4 MB
g++	04_Medium_2	AC	2 ms	4 MB
g++	04_Medium_20	AC	2 ms	4 MB
g++	04_Medium_3	AC	2 ms	4 MB
g++	04_Medium_4	AC	2 ms	4 MB
g++	04_Medium_5	AC	2 ms	4 MB
g++	04_Medium_6	AC	2 ms	4 MB
g++	04_Medium_7	AC	2 ms	4 MB
g++	04_Medium_8	AC	3 ms	4 MB
g++	04_Medium_9	AC	3 ms	4 MB
g++	05_Large_1	AC	9 ms	6 MB
g++	05_Large_10	AC	7 ms	5 MB
g++	05_Large_11	AC	4 ms	4 MB
g++	05_Large_12	AC	7 ms	5 MB
g++	05_Large_13	AC	6 ms	4 MB
g++	05_Large_14	AC	3 ms	4 MB
g++	05_Large_15	AC	5 ms	5 MB
g++	05_Large_16	AC	8 ms	5 MB
g++	05_Large_17	AC	9 ms	5 MB
g++	05_Large_18	AC	7 ms	5 MB
g++	05_Large_19	AC	9 ms	5 MB
g++	05_Large_2	AC	4 ms	4 MB
g++	05_Large_20	AC	8 ms	5 MB
g++	05_Large_3	AC	6 ms	5 MB
g++	05_Large_4	AC	5 ms	5 MB
g++	05_Large_5	AC	3 ms	4 MB
g++	05_Large_6	AC	6 ms	5 MB
g++	05_Large_7	AC	7 ms	5 MB
g++	05_Large_8	AC	4 ms	4 MB
g++	05_Large_9	AC	3 ms	4 MB
g++	06_Huge_1	AC	76 ms	24 MB
g++	06_Huge_10	AC	22 ms	9 MB
g++	06_Huge_11	AC	61 ms	18 MB
g++	06_Huge_12	AC	58 ms	19 MB
g++	06_Huge_13	AC	56 ms	19 MB
g++	06_Huge_14	AC	71 ms	24 MB
g++	06_Huge_15	AC	34 ms	10 MB
g++	06_Huge_16	AC	69 ms	19 MB
g++	06_Huge_17	AC	47 ms	16 MB
g++	06_Huge_18	AC	79 ms	25 MB
g++	06_Huge_19	AC	20 ms	8 MB
g++	06_Huge_2	AC	72 ms	19 MB
g++	06_Huge_20	AC	11 ms	6 MB
g++	06_Huge_21	AC	21 ms	8 MB
g++	06_Huge_22	AC	29 ms	11 MB
g++	06_Huge_23	AC	60 ms	18 MB
g++	06_Huge_24	AC	37 ms	13 MB
g++	06_Huge_25	AC	78 ms	26 MB
g++	06_Huge_26	AC	76 ms	21 MB
g++	06_Huge_27	AC	61 ms	18 MB
g++	06_Huge_28	AC	55 ms	17 MB
g++	06_Huge_29	AC	59 ms	17 MB
g++	06_Huge_3	AC	48 ms	15 MB
g++	06_Huge_30	AC	28 ms	10 MB
g++	06_Huge_31	AC	54 ms	18 MB
g++	06_Huge_32	AC	37 ms	13 MB
g++	06_Huge_33	AC	14 ms	6 MB
g++	06_Huge_34	AC	42 ms	15 MB
g++	06_Huge_35	AC	28 ms	10 MB
g++	06_Huge_36	AC	77 ms	21 MB
g++	06_Huge_37	AC	47 ms	15 MB
g++	06_Huge_38	AC	74 ms	22 MB
g++	06_Huge_39	AC	25 ms	9 MB
g++	06_Huge_4	AC	65 ms	20 MB
g++	06_Huge_40	AC	41 ms	14 MB
g++	06_Huge_5	AC	72 ms	20 MB
g++	06_Huge_6	AC	13 ms	7 MB
g++	06_Huge_7	AC	74 ms	21 MB
g++	06_Huge_8	AC	49 ms	14 MB
g++	06_Huge_9	AC	40 ms	12 MB
g++	07_Cycle_01	AC	2 ms	4 MB
g++	07_Cycle_02	AC	91 ms	27 MB
g++	07_Cycle_03	AC	89 ms	27 MB
clang++	01_sample_01	AC	2 ms	4 MB
clang++	01_sample_02	AC	2 ms	4 MB
clang++	01_sample_03	AC	2 ms	4 MB
clang++	02_Tiny_1	AC	2 ms	4 MB
clang++	02_Tiny_10	AC	2 ms	4 MB
clang++	02_Tiny_2	AC	2 ms	4 MB
clang++	02_Tiny_3	AC	2 ms	4 MB
clang++	02_Tiny_4	AC	2 ms	4 MB
clang++	02_Tiny_5	AC	2 ms	4 MB
clang++	02_Tiny_6	AC	2 ms	4 MB
clang++	02_Tiny_7	AC	2 ms	4 MB
clang++	02_Tiny_8	AC	2 ms	4 MB
clang++	02_Tiny_9	AC	2 ms	4 MB
clang++	03_Small1	AC	2 ms	4 MB
clang++	03_Small10	AC	2 ms	4 MB
clang++	03_Small11	AC	2 ms	4 MB
clang++	03_Small12	AC	2 ms	4 MB
clang++	03_Small13	AC	2 ms	4 MB
clang++	03_Small14	AC	2 ms	4 MB
clang++	03_Small15	AC	2 ms	4 MB
clang++	03_Small2	AC	2 ms	4 MB
clang++	03_Small3	AC	2 ms	4 MB
clang++	03_Small4	AC	2 ms	4 MB
clang++	03_Small5	AC	2 ms	4 MB
clang++	03_Small6	AC	2 ms	4 MB
clang++	03_Small7	AC	2 ms	4 MB
clang++	03_Small8	AC	2 ms	4 MB
clang++	03_Small9	AC	2 ms	4 MB
clang++	03_Small_1	AC	2 ms	4 MB
clang++	03_Small_10	AC	2 ms	4 MB
clang++	03_Small_11	AC	2 ms	4 MB
clang++	03_Small_12	AC	2 ms	4 MB
clang++	03_Small_13	AC	2 ms	4 MB
clang++	03_Small_14	AC	2 ms	4 MB
clang++	03_Small_15	AC	2 ms	4 MB
clang++	03_Small_2	AC	2 ms	4 MB
clang++	03_Small_3	AC	2 ms	4 MB
clang++	03_Small_4	AC	2 ms	4 MB
clang++	03_Small_5	AC	2 ms	4 MB
clang++	03_Small_6	AC	2 ms	4 MB
clang++	03_Small_7	AC	2 ms	4 MB
clang++	03_Small_8	AC	2 ms	4 MB
clang++	03_Small_9	AC	2 ms	4 MB
clang++	04_Medium_1	AC	2 ms	4 MB
clang++	04_Medium_10	AC	3 ms	4 MB
clang++	04_Medium_11	AC	2 ms	4 MB
clang++	04_Medium_12	AC	2 ms	4 MB
clang++	04_Medium_13	AC	2 ms	4 MB
clang++	04_Medium_14	AC	2 ms	4 MB
clang++	04_Medium_15	AC	2 ms	4 MB
clang++	04_Medium_16	AC	2 ms	4 MB
clang++	04_Medium_17	AC	2 ms	4 MB
clang++	04_Medium_18	AC	2 ms	4 MB
clang++	04_Medium_19	AC	2 ms	4 MB
clang++	04_Medium_2	AC	2 ms	4 MB
clang++	04_Medium_20	AC	2 ms	4 MB
clang++	04_Medium_3	AC	2 ms	4 MB
clang++	04_Medium_4	AC	2 ms	4 MB
clang++	04_Medium_5	AC	2 ms	4 MB
clang++	04_Medium_6	AC	2 ms	4 MB
clang++	04_Medium_7	AC	2 ms	4 MB
clang++	04_Medium_8	AC	2 ms	4 MB
clang++	04_Medium_9	AC	2 ms	4 MB
clang++	05_Large_1	AC	9 ms	6 MB
clang++	05_Large_10	AC	7 ms	5 MB
clang++	05_Large_11	AC	4 ms	4 MB
clang++	05_Large_12	AC	7 ms	5 MB
clang++	05_Large_13	AC	6 ms	4 MB
clang++	05_Large_14	AC	3 ms	4 MB
clang++	05_Large_15	AC	5 ms	4 MB
clang++	05_Large_16	AC	8 ms	5 MB
clang++	05_Large_17	AC	9 ms	5 MB
clang++	05_Large_18	AC	7 ms	5 MB
clang++	05_Large_19	AC	9 ms	5 MB
clang++	05_Large_2	AC	4 ms	4 MB
clang++	05_Large_20	AC	8 ms	5 MB
clang++	05_Large_3	AC	6 ms	5 MB
clang++	05_Large_4	AC	5 ms	5 MB
clang++	05_Large_5	AC	3 ms	4 MB
clang++	05_Large_6	AC	6 ms	5 MB
clang++	05_Large_7	AC	7 ms	5 MB
clang++	05_Large_8	AC	4 ms	4 MB
clang++	05_Large_9	AC	3 ms	4 MB
clang++	06_Huge_1	AC	76 ms	24 MB
clang++	06_Huge_10	AC	23 ms	9 MB
clang++	06_Huge_11	AC	61 ms	18 MB
clang++	06_Huge_12	AC	56 ms	19 MB
clang++	06_Huge_13	AC	55 ms	19 MB
clang++	06_Huge_14	AC	71 ms	24 MB
clang++	06_Huge_15	AC	33 ms	10 MB
clang++	06_Huge_16	AC	69 ms	19 MB
clang++	06_Huge_17	AC	46 ms	16 MB
clang++	06_Huge_18	AC	82 ms	25 MB
clang++	06_Huge_19	AC	20 ms	8 MB
clang++	06_Huge_2	AC	71 ms	19 MB
clang++	06_Huge_20	AC	11 ms	6 MB
clang++	06_Huge_21	AC	21 ms	8 MB
clang++	06_Huge_22	AC	29 ms	11 MB
clang++	06_Huge_23	AC	61 ms	18 MB
clang++	06_Huge_24	AC	37 ms	13 MB
clang++	06_Huge_25	AC	76 ms	26 MB
clang++	06_Huge_26	AC	75 ms	21 MB
clang++	06_Huge_27	AC	61 ms	18 MB
clang++	06_Huge_28	AC	56 ms	17 MB
clang++	06_Huge_29	AC	59 ms	17 MB
clang++	06_Huge_3	AC	47 ms	15 MB
clang++	06_Huge_30	AC	28 ms	10 MB
clang++	06_Huge_31	AC	55 ms	18 MB
clang++	06_Huge_32	AC	36 ms	13 MB
clang++	06_Huge_33	AC	14 ms	6 MB
clang++	06_Huge_34	AC	41 ms	15 MB
clang++	06_Huge_35	AC	27 ms	10 MB
clang++	06_Huge_36	AC	69 ms	22 MB
clang++	06_Huge_37	AC	45 ms	16 MB
clang++	06_Huge_38	AC	71 ms	22 MB
clang++	06_Huge_39	AC	25 ms	9 MB
clang++	06_Huge_4	AC	65 ms	20 MB
clang++	06_Huge_40	AC	43 ms	14 MB
clang++	06_Huge_5	AC	71 ms	20 MB
clang++	06_Huge_6	AC	13 ms	7 MB
clang++	06_Huge_7	AC	73 ms	21 MB
clang++	06_Huge_8	AC	49 ms	14 MB
clang++	06_Huge_9	AC	40 ms	13 MB
clang++	07_Cycle_01	AC	2 ms	4 MB
clang++	07_Cycle_02	AC	93 ms	27 MB
clang++	07_Cycle_03	AC	96 ms	27 MB

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