結果

問題 No.977 アリス仕掛けの摩天楼
ユーザー kissshot7kissshot7
提出日時 2020-07-19 13:56:59
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 52 ms / 2,000 ms
コード長 6,703 bytes
コンパイル時間 1,810 ms
コンパイル使用メモリ 186,428 KB
実行使用メモリ 16,304 KB
最終ジャッジ日時 2024-12-16 05:47:03
合計ジャッジ時間 3,041 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge4
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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 4 ms
7,424 KB
testcase_01 AC 5 ms
7,424 KB
testcase_02 AC 4 ms
7,424 KB
testcase_03 AC 4 ms
7,552 KB
testcase_04 AC 4 ms
7,496 KB
testcase_05 AC 4 ms
7,424 KB
testcase_06 AC 4 ms
7,552 KB
testcase_07 AC 4 ms
7,492 KB
testcase_08 AC 5 ms
7,552 KB
testcase_09 AC 4 ms
7,552 KB
testcase_10 AC 4 ms
7,492 KB
testcase_11 AC 4 ms
7,496 KB
testcase_12 AC 4 ms
7,552 KB
testcase_13 AC 9 ms
8,304 KB
testcase_14 AC 7 ms
8,008 KB
testcase_15 AC 8 ms
8,088 KB
testcase_16 AC 9 ms
8,264 KB
testcase_17 AC 9 ms
9,540 KB
testcase_18 AC 16 ms
9,856 KB
testcase_19 AC 21 ms
13,760 KB
testcase_20 AC 21 ms
10,308 KB
testcase_21 AC 36 ms
12,032 KB
testcase_22 AC 45 ms
13,252 KB
testcase_23 AC 41 ms
13,568 KB
testcase_24 AC 52 ms
16,304 KB
testcase_25 AC 42 ms
13,568 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;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = mod * mod;
const int INF_N = 1e+9;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acos(-1.0);
//typedef vector<vector<ll>> mat;
typedef vector<int> vec;

//繰り返し二乗法
ll mod_pow(ll a, ll n, ll m) {
	ll res = 1;
	while (n) {
		if (n & 1)res = res * a%m;
		a = a * a%m; n >>= 1;
	}
	return res;
}

struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n%mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint &a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint &a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint &a, modint b) { a.n = ((ll)a.n*b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
	if (n == 0)return modint(1);
	modint res = (a*a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

//逆元(Eucledean algorithm)
ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p%a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }

const int max_n = 1 << 18;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
using mP = pair<modint, modint>;

int dx[4] = { 0,1,0,-1 };
int dy[4] = { 1,0,-1,0 };


struct uf {
 
     vector<int> par;
     vector<int> sizes;
 
     uf(int n)
             : par(n), sizes(n, 1) {
         for (int i = 0; i < n; i++) {
             par[i] = i;
         }
     }
 
     int find(int x) {
         return x == par[x] ? x : par[x] = find(par[x]);
     }
 
     void unite(int x, int y) {
         x = find(x);
         y = find(y);
         if (x == y) return;
         if (sizes[x] < sizes[y]) swap(x, y);
         par[y] = x;
         sizes[x] += sizes[y];
     }
 
     bool same(int x, int y) {
         return find(x) == find(y);
     }
 
     int get_size(int x) {
         return sizes[find(x)];
     }
 
     bool all_same() {
         bool good = true;
         for (int i = 0, n = par.size(); i < n; i++) if (find(0) != find(i)) good = false;
         return good;
     }
 
     int get_connectivity() {
         set<int> s;
         for (int i = 0, n = par.size(); i < n; i++) s.insert(find(i));
         return s.size();
     }
 
 };

template<class T>
 struct Edge {
     int from, to;
     T cost;
 
     Edge(int from, int to, T cost) : from(from), to(to), cost(cost) {}
 
     explicit operator int() const { return to; }
 };
 
 template<class T>
 using Edges = vector<Edge<T>>;
 
 template<class T>
 using WeightedGraph = vector<Edges<T>>;
 
 using UnWeightedGraph = vector<vector<int>>;
 
 template<class T>
 using DistMatrix = vector<vector<T>>;
 
 struct GraphAdapter {
     template<class T>
     static UnWeightedGraph to_unweighted_graph(const WeightedGraph<T> &origin) {
         int V = origin.size();
         UnWeightedGraph graph(V);
         for (int i = 0; i < V; i++) for (auto &e: origin[i]) graph[i].push_back((int) e);
         return graph;
     }
 
     static WeightedGraph<int> to_weighted_graph(const UnWeightedGraph &origin) {
         int V = origin.size();
         WeightedGraph<int> graph(V);
         for (int i = 0; i < V; i++) for (auto to: origin[i]) graph[i].push_back({i, to, 1});
         return graph;
     }
 
     template<class T>
     static DistMatrix<T> to_dist_matrix(const WeightedGraph<T> &origin, T INF) {
         int V = origin.size();
         DistMatrix<T> matrix(V, vector<T>(V, INF));
         for (int i = 0; i < V; i++) for (auto &e:origin[i]) matrix[i][e.to] = e.cost;
         for (int i = 0; i < V; i++) matrix[i][i] = 0;
         return matrix;
     }
 };
 
 template<typename G>
 struct LowLink {
     const G &g;
 
     int k;
     vector<int> used, ord, low;
 
     vector<int> articulations;
     vector<pair<int, int>> bridges;
 
     LowLink(const G &g) : g(g) {}
 
     void dfs(int v, int p) {
         used[v] = 1;
         ord[v] = low[v] = k++;
         bool is_art = false;
         int cnt = 0;
         for (auto &to: g[v]) {
             if (!used[to]) {
                 cnt++;
                 dfs(to, v);
                 low[v] = min(low[v], low[to]);
                 is_art |= ~p && ord[v] <= low[to];
                 if (ord[v] < low[to]) bridges.emplace_back(min(v, (int) to), max(v, (int) to));
             } else if (to != p) {
                 low[v] = min(low[v], ord[to]);
             }
         }
         is_art |= p == -1 and cnt > 1;
         if (is_art) articulations.push_back(v);
     }
 
     void build() {
         int n = g.size();
         used.assign(n, 0);
         ord.assign(n, 0);
         low.assign(n, 0);
         k = 0;
         for (int i = 0; i < n; i++) {
             if (!used[i]) {
                 dfs(i, -1);
             }
         }
     }
 };

void solve() {
    int N; cin >> N;
    UnWeightedGraph G(N);
    uf u(N);
    rep(i, N-1){
        int a, b; cin >> a >> b;
        u.unite(a, b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
    int cnt = u.get_connectivity();
    if(cnt == 1){
        cout << "Bob" << endl;
        return;
    }else if(cnt >= 3){
        cout << "Alice" << endl;
        return;
    }
    LowLink<UnWeightedGraph> lowLink(G);
    lowLink.build();
    if(lowLink.bridges.size() == 0){
        cout << "Bob" << endl;
    }else{
        cout << "Alice" << endl;
    }
}

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  //cout << fixed << setprecision(10);
  //init_f();
  //init();
  //int t; cin >> t; rep(i, t)solve();
  solve();
//   stop
    return 0;
}
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