結果

問題 No.1023 Cyclic Tour
コンテスト
ユーザー Haar
提出日時 2020-04-23 11:56:47
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 119 ms / 2,000 ms
コード長 5,769 bytes
コンパイル時間 3,289 ms
コンパイル使用メモリ 206,904 KB
最終ジャッジ日時 2025-01-09 22:45:30
ジャッジサーバーID
（参考情報） 		judge1 / judge2
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ファイルパターン 結果
sample AC * 4
other AC * 49
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 i32 = int_fast32_t;
using i64 = int_fast64_t;
using u32 = uint_fast32_t;
using u64 = uint_fast64_t;
using f64 = double;
using f80 = long double;

#define FOR(v, a, b) for(i64 v = (a); v < (b); ++v)
#define FORE(v, a, b) for(i64 v = (a); v <= (b); ++v)
#define REP(v, n) FOR(v, 0, n)
#define REPE(v, n) FORE(v, 0, n)
#define REV(v, a, b) for(i64 v = (a); v >= (b); --v)
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define ITR(it, c) for(auto it = (c).begin(); it != (c).end(); ++it)
#define RITR(it, c) for(auto it = (c).rbegin(); it != (c).rend(); ++it)
#define EXIST(c,x) ((c).find(x) != (c).end())
#define fst first
#define snd second
#define UNIQ(v) (v).erase(unique(ALL(v)), (v).end())
#define bit(i) (1LL<<(i))

#ifdef DEBUG
#include <Mylib/Debug/debug.cpp>
#else
#define dump(...) ((void)0)
#endif

using namespace std;

template <typename I> void join(ostream &ost, I s, I t, string d=" "){for(auto i=s; i!=t; ++i){if(i!=s)ost<<d; ost<<*i;}ost<<endl;}
template <typename T> istream& operator>>(istream &is, vector<T> &v){for(auto &a : v) is >> a; return is;}
template <typename T> void pout(const T &value){std::cout << value << "\n";}
template <typename T, typename ...Args> void pout(const T &value, const Args&... args){std::cout << value << " ";pout(args...);}

template <typename T, typename U> bool chmin(T &a, const U &b){return (a>b ? a=b, true : false);}
template <typename T, typename U> bool chmax(T &a, const U &b){return (a<b ? a=b, true : false);}
template <typename T, size_t N, typename U> void fill_array(T (&a)[N], const U &v){fill((U*)a, (U*)(a+N), v);}
template <typename T> auto make_vector(int n, int m, const T &value){return vector<vector<T>>(n, vector<T>(m, value));}


struct Init{
  Init(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(12);
    cerr << fixed << setprecision(12);
  }
}init;


template <typename Cost = int> class Edge{
public:
  int from,to;
  Cost cost;
  Edge() {}
  Edge(int to, Cost cost): to(to), cost(cost){}
  Edge(int from, int to, Cost cost): from(from), to(to), cost(cost){}

  Edge rev() const {return Edge(to,from,cost);}
  
  friend std::ostream& operator<<(std::ostream &os, const Edge &e){
    os << "(FROM: " << e.from << "," << "TO: " << e.to << "," << "COST: " << e.cost << ")";
    return os;
  }
};

template <typename T> using Graph = std::vector<std::vector<Edge<T>>>;
template <typename T> using Tree = std::vector<std::vector<Edge<T>>>;

template <typename C, typename T> void add_edge(C &g, int from, int to, T w){
  g[from].emplace_back(from, to, w);
}

template <typename C, typename T> void add_undirected(C &g, int a, int b, T w){
  add_edge(g, a, b, w);
  add_edge(g, b, a, w);
}



class UnionFind{
  std::vector<int> parent, depth, size;
  int count;

public:
  UnionFind(int n): parent(n), depth(n,1), size(n,1), count(n){
    std::iota(parent.begin(), parent.end(), 0);
  }
  
  inline int get_root(int i){
    if(parent[i] == i) return i;
    else return parent[i] = get_root(parent[i]);
  }
  
  inline bool is_same(int i, int j){return get_root(i) == get_root(j);}

  inline int merge(int i, int j){
    int ri = get_root(i), rj = get_root(j);
    if(ri == rj) return ri;
    else{
      --count;
      if(depth[ri] < depth[rj]){
        parent[ri] = rj;
        size[rj] += size[ri];
        return rj;
      }else{
        parent[rj] = ri;
        size[ri] += size[rj];
        if(depth[ri] == depth[rj]) ++depth[ri];
        return ri;
      }
    }
  }

  inline int get_size(int i){return size[get_root(i)];}

  inline int count_group(){return count;}
};


template <typename T>
struct SCC{
  std::vector<int> result;
  int scc_size;
  
private:
  std::vector<bool> visit;
  std::vector<int> check;
  
  void dfs(int cur, const Graph<T> &graph){
    visit[cur] = true;
    for(auto &e : graph[cur]){
      if(not visit[e.to]) dfs(e.to,graph);
    }
    check.push_back(cur);
  }

  void rdfs(int cur, int i, const Graph<T> &rgraph){
    result[cur] = i;
    for(auto &e : rgraph[cur]){
      if(result[e.to] == -1) rdfs(e.to,i,rgraph);
    }
  }

public:
  SCC(const Graph<T> &graph){
    const int n = graph.size();
    result.assign(n, -1);
    visit.assign(n, false);
    
    for(int i = 0; i < n; ++i) if(!visit[i]) dfs(i,graph);
    std::reverse(check.begin(), check.end());
    
    Graph<T> rgraph(n);
    for(int i = 0; i < n; ++i) for(auto &e : graph[i]) rgraph[e.to].push_back(e.rev());

    int i = 0;
    for(auto c : check) if(result[c] == -1) {rdfs(c,i,rgraph); ++i;}
    scc_size = i;
  }

  inline const int operator[](int i) const {return result[i];}
};


template <typename T>
bool detect_cycle(const Graph<T> &g){
  const int N = g.size();

  std::vector<int> check(N);

  auto dfs =
    [&](auto &dfs, int cur) -> bool{
      if(check[cur] != 0) return false;

      check[cur] = 2;

      for(auto &e : g[cur]){
        if(check[e.to] == 2) return true;
        if(check[e.to] == 0){
          if(dfs(dfs, e.to)) return true;
        }
      }

      check[cur] = 1;

      return false;
    };

  for(int i = 0; i < N; ++i){
    if(check[i] == 0 and dfs(dfs, i)) return true;
  }

  return false;
}



int main(){
  int N, M;

  while(cin >> N >> M){
    Graph<int> g(N);
    UnionFind uf(N);

    bool ans = false;

    vector<pair<int,int>> de;
    
    REP(i,M){
      int a, b, c; cin >> a >> b >> c;
      --a, --b;
      
      if(c == 1){
        if(uf.is_same(a, b)) ans = true;
        uf.merge(a, b);
      }else{
        de.emplace_back(a, b);
      }
    }

    for(auto &[a,b] : de){
      add_edge(g, uf.get_root(a), uf.get_root(b), 1);
    }

    if(detect_cycle(g)) ans = true;
    
    pout(ans ? "Yes" : "No");
  }

  return 0;
}
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