oj.uz

답안 #634670

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
634670 2022-08-24T16:49:00 Z S2speed Subtree (INOI20_subtree) C++17
12 / 100
 96 ms 33996 KB 
#include<bits/stdc++.h>

using namespace std;

#pragma GCC optimize ("Ofast")

#define all(x) x.begin() , x.end()
#define sze(x) (ll)(x.size())
#define mp(x , y) make_pair(x , y)
#define wall cerr<<"--------------------------------------"<<endl
typedef long long int ll;
typedef pair<ll , ll> pll;
typedef pair<int , int> pii;
typedef long double db;
typedef pair<pll , ll> plll;
typedef pair<int , pii> piii;
typedef pair<pll , pll> pllll;

const ll maxn = 2e5 + 17 , md = 1e9 + 7 , inf = 2e16;

ll n , m , ans;
bitset<maxn> mark;
vector<ll> adj[maxn] , cc[maxn] , st , del , v;
vector<pll> cdj[maxn];
ll c[maxn] , o , dp[maxn] , ps[maxn] , pz[maxn];

void cDFS(ll r , ll par){
	st.push_back(r);
	mark[r] = true;
	for(auto i : adj[r]){
		if(i == par) continue;
		if(mark[i]){
			if(c[r] != -1) continue;
			while(st.back() != i){
				c[st.back()] = o;
				cc[o].push_back(st.back());
				del.push_back(st.back());
				st.pop_back();
			}
			c[i] = o;
			cc[o].push_back(i);
			o++;
			while(!del.empty()){
				st.push_back(del.back());
				del.pop_back();
			}
			continue;
		}
		cDFS(i , r);
	}
	st.pop_back();
	return;
}

ll cal(ll l , ll r){
	if(l >= r) return 0;
	if(r - l == 1) return v[l];
	ll m = (r + l) >> 1;
	ll a = 1 , b = 1 , h = 1;
	for(ll i = m - 1 ; i >= l ; i--){
		h *= v[i]; h %= md;
		a += h;
	}
	h = 1;
	for(ll i = m + 1 ; i < r ; i++){
		h *= v[i]; h %= md;
		b += h;
	}
	a %= md; b %= md;
	ll res = cal(l , m) + cal(m + 1 , r) + a * b % md * v[m];
	return res % md;
}

void dDFS(ll r , ll t , ll par , bool f = false){
//	cout<<r<<' '<<t<<' '<<par<<' '<<f<<endl;
	if(r < n){
		ll h = 1;
		for(auto p : cdj[r]){
			ll i = p.first , u = p.second;
			if(i == par) continue;
			dDFS(i , u , r);
			h *= dp[i] + 1; h %= md;
		}
		dp[r] = h;
		ans += h;
		return;
	}
	swap(r , t);
	if(f){
		ll h = 1;
		for(auto i : adj[r]){
			ll u = (c[i] == -1 ? i : c[i]);
			if(u == t) continue;
			dDFS(u , i , t);
			h *= dp[u] + 1; h %= md;
		}
		dp[r] = h;
		return;
	}
	ll ind = -1 , sz = sze(cc[t]);
	for(ll i = 0 ; i < sz ; i++){
		if(cc[t][i] == r){
			ind = i;
			break;
		}
	}
	v.clear();
	for(ll i = ind + 1 ; i < sz ; i++){
		dDFS(t , cc[t][i] , par , true);
		v.push_back(dp[cc[t][i]]);
	}
	for(ll i = 0 ; i < ind ; i++){
		dDFS(t , cc[t][i] , par , true);
		v.push_back(dp[cc[t][i]]);
	}
	ll vs = sz - 1;
	ps[0] = v[0] + 1;
	pz[0] = v[0];
	for(ll i = 1 ; i < vs ; i++){
		pz[i] = pz[i - 1] * v[i] % md;
		ps[i] = ps[i - 1] + pz[i]; ps[i] -= (ps[i] >= md) * md;
	}
	ll cur = 1 , res = 0;
	for(ll i = vs - 1 ; i > 0 ; i--){
		ll h = cur * ps[i - 1] % md;
		res += h;
		cur *= v[i]; cur %= md;
	}
	res += cur;
	dp[t] = res % md;
	ans += dp[t];
	ans += cal(0 , vs);
	return;
}

int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

	memset(c , -1 , sizeof(c));
	cin>>n>>m; o = n;
	for(ll i = 0 ; i < m ; i++){
		ll v , u;
		cin>>v>>u; v--; u--;
		adj[v].push_back(u); adj[u].push_back(v);
	}
	cDFS(0 , -1);
	for(ll i = 0 ; i < n ; i++){
		ll v = (c[i] == -1 ? i : c[i]);
		for(auto j : adj[i]){
			ll u = (c[j] == -1 ? j : c[j]);
			if(v == u) continue;
			cdj[v].push_back({u , j});
		}
	}
	dDFS((c[0] == -1 ? 0 : c[0]) , 0 , -1);
	ans %= md;
	cout<<ans<<'\n';
	return 0;
}

Subtask #1
0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 15956 KB Output is correct
2 Correct 9 ms 15984 KB Output is correct
3 Incorrect 8 ms 15992 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
12.0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 15992 KB Output is correct
2 Correct 13 ms 16848 KB Output is correct
3 Correct 65 ms 25628 KB Output is correct
4 Correct 67 ms 25552 KB Output is correct
5 Correct 78 ms 25636 KB Output is correct
6 Correct 71 ms 25612 KB Output is correct
7 Correct 85 ms 32200 KB Output is correct
8 Correct 78 ms 29928 KB Output is correct
9 Correct 85 ms 30284 KB Output is correct
10 Correct 54 ms 26152 KB Output is correct
11 Correct 63 ms 25108 KB Output is correct
12 Correct 67 ms 24584 KB Output is correct
13 Correct 69 ms 24532 KB Output is correct
14 Correct 57 ms 28120 KB Output is correct
15 Correct 95 ms 33060 KB Output is correct
16 Correct 96 ms 33996 KB Output is correct
17 Correct 69 ms 24656 KB Output is correct
18 Correct 72 ms 24700 KB Output is correct
19 Correct 71 ms 24628 KB Output is correct
20 Correct 55 ms 25396 KB Output is correct
21 Correct 64 ms 25448 KB Output is correct
22 Correct 54 ms 25428 KB Output is correct

Subtask #3
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 15956 KB Output is correct
2 Correct 9 ms 15984 KB Output is correct
3 Incorrect 8 ms 15992 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 50.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 15956 KB Output is correct
2 Correct 9 ms 15984 KB Output is correct
3 Incorrect 8 ms 15992 KB Output isn't correct
4 Halted 0 ms 0 KB -