結果
| 問題 |
No.977 アリス仕掛けの摩天楼
|
| ユーザー |
 kissshot7
|
| 提出日時 | 2020-07-19 13:56:59 |
| 言語 | C++14 (gcc 13.3.0 + boost 1.87.0) |
| 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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| ファイルパターン | 結果 |
|---|---|
| other | AC * 26 |
ソースコード
#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;
}