結果

問題 No.977 アリス仕掛けの摩天楼
ユーザー Haar
提出日時 2020-01-31 21:52:26
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 73 ms / 2,000 ms
コード長 4,412 bytes
コンパイル時間 2,418 ms
コンパイル使用メモリ 205,100 KB
最終ジャッジ日時 2025-01-08 21:04:14
ジャッジサーバーID
（参考情報） 		judge1 / judge3
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ファイルパターン 結果
other AC * 26
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>
#define LLI long long int
#define FOR(v, a, b) for(LLI v = (a); v < (b); ++v)
#define FORE(v, a, b) for(LLI 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(LLI 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 popcount __builtin_popcount
#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

#define gcd __gcd

using namespace std;
template <class T> constexpr T lcm(T m, T n){return m/gcd(m,n)*n;}

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 puts_all(const T &value){std::cout << value << "\n";}
template <typename T, typename ...Args> void puts_all(const T &value, const Args&... args){std::cout << value << " ";puts_all(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].push_back(Edge<T>(from, to, w));  
}

template <typename C, typename T> void add_undirected(C &g, int a, int b, T w){
  g[a].push_back(Edge<T>(a, b, w));
  g[b].push_back(Edge<T>(b, a, w));
}



template <typename T> std::vector<Edge<T>> bridges(const Graph<T> &graph){
  int n = graph.size();
  std::vector<int> visit(n,-1), low(n,-1);
  std::vector<Edge<T>> ret;
  int v = 0;
  auto dfs =
    [&](auto &dfs, int cur, int par) -> int{
      if(visit[cur] != -1) return visit[cur];
      visit[cur] = v;
      int temp = v;
      ++v;
      for(auto &e : graph[cur]){
        if(e.to == par) continue;
        int t = dfs(dfs, e.to, cur);
        temp = std::min(temp, t);
        if(low[e.to] > visit[cur]) ret.push_back(e);
      }  
      return low[cur] = temp;
    };
  
  for(int i = 0; i < n; ++i) if(visit[i] == -1) dfs(dfs, i, -1);
  return ret;
}


template <typename T>
int count_connected_components(const Graph<T> &g){
  int n = g.size();

  int ret = 0;
  vector<bool> visit(n);

  auto dfs =
    [&](auto &dfs, int cur, int par) -> void{
      if(visit[cur]) return;
      visit[cur] = true;

      for(auto &e : g[cur]){
        if(e.to == par) continue;
        dfs(dfs, e.to, cur);
      }
    };

  for(int i = 0; i < n; ++i){
    if(not visit[i]){
      dfs(dfs, i, -1);
      ++ret;
    }
  }

  return ret;
}

int main(){
  int N;
  while(cin >> N){
    Graph<int> g(N);
    REP(i,N-1){
      int u,v; cin >> u >> v;
      add_undirected(g, u, v, 1);
    }

    int c = count_connected_components(g);

    dump(c);

    if(c == 1){
      puts_all("Bob");
    }else if(c > 2){
      puts_all("Alice");
    }else{
      auto b = bridges(g);

      dump(b);

      if(b.empty()){
        puts_all("Bob");
      }else{
        puts_all("Alice");
      }
    }
  }
  
  return 0;
}
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