結果

問題 No.1124 Earthquake Safety
ユーザー maroon_kurimaroon_kuri
提出日時 2020-07-22 22:31:43
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 462 ms / 3,000 ms
コード長 7,908 bytes
コンパイル時間 3,633 ms
コンパイル使用メモリ 211,072 KB
実行使用メモリ 103,876 KB
最終ジャッジ日時 2023-09-05 02:18:55
合計ジャッジ時間 29,920 ms
ジャッジサーバーID
（参考情報） 		judge11 / judge15
このコードへのチャレンジ
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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 32 ms
27,932 KB
testcase_01 AC 33 ms
28,224 KB
testcase_02 AC 32 ms
27,972 KB
testcase_03 AC 32 ms
28,236 KB
testcase_04 AC 32 ms
28,228 KB
testcase_05 AC 32 ms
27,988 KB
testcase_06 AC 32 ms
28,120 KB
testcase_07 AC 37 ms
28,840 KB
testcase_08 AC 137 ms
39,564 KB
testcase_09 AC 432 ms
63,352 KB
testcase_10 AC 217 ms
103,876 KB
testcase_11 AC 32 ms
27,944 KB
testcase_12 AC 31 ms
28,096 KB
testcase_13 AC 32 ms
28,248 KB
testcase_14 AC 455 ms
63,436 KB
testcase_15 AC 454 ms
63,596 KB
testcase_16 AC 437 ms
63,356 KB
testcase_17 AC 444 ms
63,584 KB
testcase_18 AC 449 ms
63,580 KB
testcase_19 AC 455 ms
63,456 KB
testcase_20 AC 448 ms
63,488 KB
testcase_21 AC 457 ms
63,488 KB
testcase_22 AC 462 ms
63,464 KB
testcase_23 AC 408 ms
62,992 KB
testcase_24 AC 422 ms
62,932 KB
testcase_25 AC 417 ms
63,328 KB
testcase_26 AC 410 ms
63,312 KB
testcase_27 AC 394 ms
65,548 KB
testcase_28 AC 387 ms
65,456 KB
testcase_29 AC 403 ms
72,948 KB
testcase_30 AC 400 ms
72,960 KB
testcase_31 AC 403 ms
88,732 KB
testcase_32 AC 399 ms
85,928 KB
testcase_33 AC 391 ms
83,488 KB
testcase_34 AC 394 ms
86,844 KB
testcase_35 AC 388 ms
64,040 KB
testcase_36 AC 358 ms
63,316 KB
testcase_37 AC 358 ms
65,120 KB
testcase_38 AC 367 ms
64,564 KB
testcase_39 AC 360 ms
63,852 KB
testcase_40 AC 349 ms
64,832 KB
testcase_41 AC 347 ms
63,856 KB
testcase_42 AC 348 ms
64,444 KB
testcase_43 AC 347 ms
65,024 KB
testcase_44 AC 338 ms
64,908 KB
testcase_45 AC 340 ms
64,276 KB
testcase_46 AC 332 ms
64,900 KB
testcase_47 AC 334 ms
64,208 KB
testcase_48 AC 334 ms
64,100 KB
testcase_49 AC 336 ms
64,140 KB
testcase_50 AC 32 ms
28,096 KB
testcase_51 AC 31 ms
27,972 KB
testcase_52 AC 32 ms
28,244 KB
testcase_53 AC 31 ms
27,940 KB
testcase_54 AC 32 ms
27,972 KB
testcase_55 AC 32 ms
27,940 KB
testcase_56 AC 32 ms
28,044 KB
testcase_57 AC 32 ms
27,968 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;

using ll=long long;
#define int ll

#define rng(i,a,b) for(int i=int(a);i<int(b);i++)
#define rep(i,b) rng(i,0,b)
#define gnr(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define per(i,b) gnr(i,0,b)
#define pb push_back
#define eb emplace_back
#define a first
#define b second
#define bg begin()
#define ed end()
#define all(x) x.bg,x.ed
#define si(x) int(x.size())
#ifdef LOCAL
#define dmp(x) cerr<<__LINE__<<" "<<#x<<" "<<x<<endl
#else
#define dmp(x) void(0)
#endif

template<class t,class u> void chmax(t&a,u b){if(a<b)a=b;}
template<class t,class u> void chmin(t&a,u b){if(b<a)a=b;}

template<class t> using vc=vector<t>;
template<class t> using vvc=vc<vc<t>>;

using pi=pair<int,int>;
using vi=vc<int>;

template<class t,class u>
ostream& operator<<(ostream& os,const pair<t,u>& p){
	return os<<"{"<<p.a<<","<<p.b<<"}";
}

template<class t> ostream& operator<<(ostream& os,const vc<t>& v){
	os<<"{";
	for(auto e:v)os<<e<<",";
	return os<<"}";
}

#define mp make_pair
#define mt make_tuple
#define one(x) memset(x,-1,sizeof(x))
#define zero(x) memset(x,0,sizeof(x))
#ifdef LOCAL
void dmpr(ostream&os){os<<endl;}
template<class T,class... Args>
void dmpr(ostream&os,const T&t,const Args&... args){
	os<<t<<" ";
	dmpr(os,args...);
}
#define dmp2(...) dmpr(cerr,__LINE__,##__VA_ARGS__)
#else
#define dmp2(...) void(0)
#endif

using uint=unsigned;
using ull=unsigned long long;

template<class t,size_t n>
ostream& operator<<(ostream&os,const array<t,n>&a){
	return os<<vc<t>(all(a));
}

template<int i,class T>
void print_tuple(ostream&,const T&){
}

template<int i,class T,class H,class ...Args>
void print_tuple(ostream&os,const T&t){
	if(i)os<<",";
	os<<get<i>(t);
	print_tuple<i+1,T,Args...>(os,t);
}

template<class ...Args>
ostream& operator<<(ostream&os,const tuple<Args...>&t){
	os<<"{";
	print_tuple<0,tuple<Args...>,Args...>(os,t);
	return os<<"}";
}

template<class t>
void print(t x,int suc=1){
	cout<<x;
	if(suc==1)
		cout<<"\n";
	if(suc==2)
		cout<<" ";
}

ll read(){
	ll i;
	cin>>i;
	return i;
}

vi readvi(int n,int off=0){
	vi v(n);
	rep(i,n)v[i]=read()+off;
	return v;
}

template<class T>
void print(const vector<T>&v,int suc=1){
	rep(i,v.size())
		print(v[i],i==int(v.size())-1?suc:2);
}

string readString(){
	string s;
	cin>>s;
	return s;
}

template<class T>
T sq(const T& t){
	return t*t;
}

//#define CAPITAL
void yes(bool ex=true){
	#ifdef CAPITAL
	cout<<"YES"<<"\n";
	#else
	cout<<"Yes"<<"\n";
	#endif
	if(ex)exit(0);
}
void no(bool ex=true){
	#ifdef CAPITAL
	cout<<"NO"<<"\n";
	#else
	cout<<"No"<<"\n";
	#endif
	if(ex)exit(0);
}
void possible(bool ex=true){
	#ifdef CAPITAL
	cout<<"POSSIBLE"<<"\n";
	#else
	cout<<"Possible"<<"\n";
	#endif
	if(ex)exit(0);
}
void impossible(bool ex=true){
	#ifdef CAPITAL
	cout<<"IMPOSSIBLE"<<"\n";
	#else
	cout<<"Impossible"<<"\n";
	#endif
	if(ex)exit(0);
}

constexpr ll ten(int n){
	return n==0?1:ten(n-1)*10;
}

const ll infLL=LLONG_MAX/3;

#ifdef int
const int inf=infLL;
#else
const int inf=INT_MAX/2-100;
#endif

int topbit(signed t){
	return t==0?-1:31-__builtin_clz(t);
}
int topbit(ll t){
	return t==0?-1:63-__builtin_clzll(t);
}
int botbit(signed a){
	return a==0?32:__builtin_ctz(a);
}
int botbit(ll a){
	return a==0?64:__builtin_ctzll(a);
}
int popcount(signed t){
	return __builtin_popcount(t);
}
int popcount(ll t){
	return __builtin_popcountll(t);
}
bool ispow2(int i){
	return i&&(i&-i)==i;
}
ll mask(int i){
	return (ll(1)<<i)-1;
}

bool inc(int a,int b,int c){
	return a<=b&&b<=c;
}

template<class t> void mkuni(vc<t>&v){
	sort(all(v));
	v.erase(unique(all(v)),v.ed);
}

ll rand_int(ll l, ll r) { //[l, r]
	#ifdef LOCAL
	static mt19937_64 gen;
	#else
	static mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());
	#endif
	return uniform_int_distribution<ll>(l, r)(gen);
}

template<class t>
void myshuffle(vc<t>&a){
	rep(i,si(a))swap(a[i],a[rand_int(0,i)]);
}

template<class t>
int lwb(const vc<t>&v,const t&a){
	return lower_bound(all(v),a)-v.bg;
}

struct modinfo{uint mod,root;};
template<modinfo const&ref>
struct modular{
	static constexpr uint const &mod=ref.mod;
	static modular root(){return modular(ref.root);}
	uint v;
	//modular(initializer_list<uint>ls):v(*ls.bg){}
	modular(ll vv=0){s(vv%mod+mod);}
	modular& s(uint vv){
		v=vv<mod?vv:vv-mod;
		return *this;
	}
	modular operator-()const{return modular()-*this;}
	modular& operator+=(const modular&rhs){return s(v+rhs.v);}
	modular&operator-=(const modular&rhs){return s(v+mod-rhs.v);}
	modular&operator*=(const modular&rhs){
		v=ull(v)*rhs.v%mod;
		return *this;
	}
	modular&operator/=(const modular&rhs){return *this*=rhs.inv();}
	modular operator+(const modular&rhs)const{return modular(*this)+=rhs;}
	modular operator-(const modular&rhs)const{return modular(*this)-=rhs;}
	modular operator*(const modular&rhs)const{return modular(*this)*=rhs;}
	modular operator/(const modular&rhs)const{return modular(*this)/=rhs;}
	modular pow(int n)const{
		modular res(1),x(*this);
		while(n){
			if(n&1)res*=x;
			x*=x;
			n>>=1;
		}
		return res;
	}
	modular inv()const{return pow(mod-2);}
	/*modular inv()const{
		int x,y;
		int g=extgcd<ll>(v,mod,x,y);
		assert(g==1);
		if(x<0)x+=mod;
		return modular(x);
	}*/
	friend modular operator+(int x,const modular&y){
		return modular(x)+y;
	}
	friend modular operator-(int x,const modular&y){
		return modular(x)-y;
	}
	friend modular operator*(int x,const modular&y){
		return modular(x)*y;
	}
	friend modular operator/(int x,const modular&y){
		return modular(x)/y;
	}
	friend ostream& operator<<(ostream&os,const modular&m){
		return os<<m.v;
	}
	friend istream& operator>>(istream&is,modular&m){
		ll x;is>>x;
		m=modular(x);
		return is;
	}
	bool operator<(const modular&r)const{return v<r.v;}
	bool operator==(const modular&r)const{return v==r.v;}
	bool operator!=(const modular&r)const{return v!=r.v;}
	explicit operator bool()const{
		return v;
	}
};

//extern constexpr modinfo base{998244353,3};
extern constexpr modinfo base{1000000007,0};
//modinfo base{1,0};
using mint=modular<base>;

const int vmax=(1<<21)+10;
mint fact[vmax],finv[vmax],invs[vmax];
void initfact(){
	fact[0]=1;
	rng(i,1,vmax){
		fact[i]=fact[i-1]*i;
	}
	finv[vmax-1]=fact[vmax-1].inv();
	for(int i=vmax-2;i>=0;i--){
		finv[i]=finv[i+1]*(i+1);
	}
	for(int i=vmax-1;i>=1;i--){
		invs[i]=finv[i]*fact[i-1];
	}
}
mint choose(int n,int k){
	return fact[n]*finv[n-k]*finv[k];
}
mint binom(int a,int b){
	return fact[a+b]*finv[a]*finv[b];
}
mint catalan(int n){
	return binom(n,n)-(n-1>=0?binom(n-1,n+1):0);
}

//AGC034E
//XX Opencup GP of Korea
//CF446D
//int(E)->to
template<class N,class E>
struct treedp{
	const vvc<E>& g;
	vc<N> a,b,res,sub,bus;
	void dfs1(int v,int p){
		a[v].init(v);
		E up;
		for(auto e:g[v])
			if(e!=p){
				dfs1(e,v);
				b[e]=a[v];
				a[v]=a[v]+a[e];
			}else
				up=e;
		sub[v]=a[v];
		if(p!=-1)a[v]=a[v].up(up);
	}
	void dfs2(int v,int p,N cur){
		per(i,g[v].size()){
			auto e=g[v][i];
			if(e==p)continue;
			bus[e]=cur+b[e];
			dfs2(e,v,bus[e].up(e));
			cur=cur+a[e];
		}
		res[v]=cur;
	}
	treedp(const vvc<E>&gg):g(gg),a(si(g)),b(si(g)),res(si(g)),sub(si(g)),bus(si(g)){
		dfs1(0,-1);
		N tmp;tmp.init(0);
		dfs2(0,-1,tmp);
	}
};

struct N{
	mint a[3];
	void init(int){
		a[0]=1;
		a[1]=0;
		a[2]=0;
	}
	N addself()const{
		N res=*this;
		res.a[2]+=a[0]+a[1]*2;
		res.a[1]+=a[0];
		return res;
	}
	N up(int)const{
		N res=addself();
		rng(i,1,3)res.a[i]*=invs[2];
		return res;
	}
	N operator+(const N&r)const{
		N res;
		res.a[0]=0;
		rep(i,3)rep(j,3-i){
			res.a[i+j]+=a[i]*r.a[j]*(i==1&&j==1?2:1);
		}
		return res;
	}
};

signed main(){
	cin.tie(0);
	ios::sync_with_stdio(0);
	cout<<fixed<<setprecision(20);
	
	initfact();
	int n;cin>>n;
	vvc<int> t(n);
	rep(i,n-1){
		int a,b;cin>>a>>b;
		a--;b--;
		t[a].pb(b);
		t[b].pb(a);
	}
	treedp<N,int> dp(t);
	mint ans=0;
	rep(i,n){
		ans+=dp.res[i].addself().a[2];
	}
	print(ans*mint(2).pow(n-1));
}
0