Submission #469899

#	Time	Username	Problem	Language	Result	Execution time	Memory
469899		MohammadParsaElahimanesh	Sumtree (INOI20_sumtree)	C++14	10 / 100	3072 ms	51248 KiB

Main

/// In the name of Allah

#include <bits/stdc++.h>

using namespace std;

#define Fast ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define RFOR(i,a) for(int i = a-1; i >= 0; i--)
#define FOR(i,a) for(int i = 0; i < a; i++)
#define se second
#define fi first
#define sz(x) (int)x.size()
#define upp upper_bound
#define low lower_bound
#define pub push_back
#define all(x) x.begin(),x.end()
#define mp make_pair

typedef double ld;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;

const ll mod = 1'000'000'007;
const int N = 200'000 + 5;
const int Z = 2*500'000 + 5;
ll F[Z], _F[Z], ans;
int n, r, q, H[N], S[N], dad[N], st[N], en[N], R[N], B[N], tag[N], timer = 1, p = 0, cnt = 0;
set<pii> X[N];
vector<int> G[N];

inline ll Pow(ll a, int b)
{
	ll res = 1LL;
	while(b)
	{
		if(b&1)res = res*a%mod;
		b >>= 1;
		a = a*a%mod;
	}
	return res;
}

inline ll inv(int x){return Pow(x,mod-2);}

inline ll C(int x, int y)
{
	if(max(x,y) >= Z)while(true);
	if(x > y || x < 0)return 0;
	return F[y]*_F[x]%mod*_F[y-x]%mod;
}

struct fen
{
	int G[N];
	fen(){memset(G,0,sizeof(G));}
	inline void inc(int p, int x)
	{
		while(p < N)
		{
			G[p] += x;
			p += p&-p;
		}
	}
	inline int get(int p)
	{
		int s = 0;
		while(p)
		{
			s += G[p];
			p -= p&-p;
		}
		return s;
	}
}tags, Free;


int dfs_s(int v, int d, int h)
{
	st[v] = timer++;
	H[v] = h;
	dad[v] = d;
	S[v] = 1;
	for(auto u: G[v])if(u != d)S[v] += dfs_s(u,v,h+1);
	en[v] = timer;
	return S[v];
}

void dfs_hld(int v, int top, int nam)
{
	R[v] = nam;
	B[v] = top;
	pii MAX = mp(-1,-2);
	for(auto u: G[v])if(u != dad[v])MAX = max(MAX,mp(S[u],u));
	for(auto u: G[v])if(u != dad[v])
	{
		if(MAX.se == u)dfs_hld(u,top,nam);
		else dfs_hld(u,u,p++);
	}
}

inline int first_up(int v)
{
	auto top = X[R[v]].upp(mp(H[v],v));
	if(top == X[R[v]].begin())
	{
		v = dad[B[v]];
		return first_up(v);
	}
	else
	{
		--top;
		return (*top).se;
	}
}

inline void upd(int v, int tg, int fs)
{
	int nfs = S[v]-Free.get(en[v]-1)+Free.get(st[v]);
	int ntg = tag[v]-tags.get(en[v]-1)+tags.get(st[v]);
	
	if(C(ntg,nfs+ntg-1) == 0)cnt++;
	else ans = ans*C(ntg,nfs+ntg-1)%mod;
	
	nfs += fs;
	ntg += tg;
	
	if(C(ntg,nfs+ntg-1) == 0)cnt--;
	else ans = ans*inv(C(ntg,nfs+ntg-1))%mod;
}

int main()
{
	Fast
	
	F[0] = 1;
	for(ll i = 1; i < Z; i++)F[i] = i*F[i-1]%mod;
	_F[Z-1] = inv(F[Z-1]);
	for(ll i = Z-2; i >= 0; i--)_F[i] = (i+1LL)*_F[i+1]%mod;
	
	cin >> n >> r;
	
	int u, v, x, t;
	FOR(i,n-1)
	{
		cin >> u >> v;
		u--; v--;
		G[u].pub(v); G[v].pub(u);
	}
	dfs_s(0,0,0);
	dfs_hld(0,0,p++);
	tag[0] = r;
	X[R[0]].insert(mp(0,0));
	tags.inc(st[0],r);
	Free.inc(st[0],n);
	ans = C(r,n+r-1);
	cout << ans << '\n';
	
	cin >> q;
	
	FOR(i,q)
	{
		cin >> t;
		if(t == 1)
		{
			cin >> v >> x;
			v--;
			tag[v] = x;
			u = first_up(v);
			
			int fs = S[v]-Free.get(en[v]-1)+Free.get(st[v]);
			int tg = x-tags.get(en[v]-1)+tags.get(st[v]);
			Free.inc(st[v],fs);
			tags.inc(st[v],tg);
			
			if(C(tg,fs+tg-1) == 0)cnt++;
			else ans = (ans*C(tg,fs+tg-1))%mod;
			upd(u,tg,fs);
			X[R[v]].insert(mp(H[v],v));
		}
		else
		{
			cin >> v;
			v--;
			return 0;
		}
		
		cout << (cnt?0:ans) << '\n';
	}
	
	return 0;
}

// thank god

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30