Submission #464554

#	Time	Username	Problem	Language	Result	Execution time	Memory
464554		Return_0	Sumtree (INOI20_sumtree)	C++17	50 / 100	608 ms	63028 KiB

Main

#pragma GCC optimize("Ofast,unroll-loops")
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma,tune=native")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

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

#ifdef SINA
#define dbg(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1> void __f(const char* name, Arg1&& arg1) { cout << name << " : " << arg1 << std::endl; }
template <typename Arg1, typename... Args> void __f (const char* names, Arg1&& arg1, Args&&... args) {
	const char* comma = strchr(names + 1, ',');cout.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...); }
#define dbg2(x, j, n) cout<< #x << " : "; output((j), (n), x, 1); cout.flush();
#else
#define dbg(...) 0
#define dbg2(x, j, n) 0
#endif
#define SZ(x) ((ll)((x).size()))
#define File(s, t) freopen(s ".txt", "r", stdin); freopen(t ".txt", "w", stdout);
#define input(j, n, a) for (int _i = (j); _i < (n)+(j); _i++) cin>> a[_i];
#define output(j, n, a, t) for (int _i = (j); _i < (n)+(j); _i++) cout<< a[_i] << (((t) && _i != (n)+(j)-1)? ' ' : '\n');
#define kill(x) return cout<< (x) << endl, 0
#define cl const ll
#define fr first
#define sc second
#define lc (v << 1)
#define rc (lc | 1)
#define mid ((l + r) >> 1)
#define All(x) (x).begin(), (x).end()

const lol inf = sizeof(lol) == 4 ? (1e9 + 10) : (3e18), mod = 1e9 + 7, MOD = 998244353;

template <class A,class B> ostream& operator << (ostream& out,const pair<A,B>&a){return out<<'('<<a.first<<", "<<a.second<<')';}
template <class A> ostream& operator << (ostream& out, const vector<A> &a) {
	out<< '['; for (int i = -1; ++i < int(a.size());) out<< a[i] << (i + 1 < int(a.size()) ? ", " : ""); return out<<']'; }
template <class T, typename _t = less <T> > using Tree = tree <T, null_type, _t, rb_tree_tag, tree_order_statistics_node_update>;

cl N = 5e5 + 7;

inline lol bpow (lol x, ll n) { lol t = 1; for (; n; n >>= 1, x = x * x % mod) if (n & 1) t = t * x % mod; return t; }
inline lol Inv (cl &x) { return bpow(x, mod - 2); }

lol f [N], inv [N], ans;
ll tin [N], tout [N], rtin [N], c [N], sz [N], n, r, q, zero, T;
vector <ll> adj [N];

void DFS (cl &v = 1, cl &pr = 0) {
	rtin[tin[v] = ++T] = v;
	for (auto &u : adj[v]) if (u != pr) DFS(u, v);
	tout[v] = T;
}

struct segtree {
	ll l, r, mx;
	segtree *lt, *rt;
	inline segtree (cl &L = 1, cl &R = N - 2) : l(L), r(R), mx(0) {}

	void build () {
		if (l == r) return;
		lt = new segtree (l, mid);
		rt = new segtree (mid + 1, r);
		lt->build();
		rt->build();
	}

	void upd (cl &pos, cl &x) {
		if (l == r) { mx = x; return; }
		if (pos <= lt->r) lt->upd(pos, x);
		else rt->upd(pos, x);
		mx = max(lt->mx, rt->mx);
	}

	ll ask (cl &qr, cl &x) {
		if (qr < l || mx < x) return 0;
		if (l == r) return l;
		if (r <= qr) {
			if (rt->mx >= x) return rt->ask(qr, x);
			return lt->ask(qr, x);
		}
		ll p = rt->ask(qr, x);
		if (!p) p = lt->ask(qr, x);
		return p;
	}
} seg;

struct fenwick {
	lol fen [N];
	fenwick () { memset(fen, 0, sizeof fen); }
	inline void add (ll i, const lol &x) { for (; i < N; i += i & -i) fen[i] += x; }
	inline ll ask (ll l, ll r) {
		ll ret = 0;
		for (; r; r -= r & -r) ret += fen[r];
		for (l--; l; l -= l & -l) ret -= fen[l];
		return ret;
	}
} fen, fen2;

inline lol nCr (cl &n, cl &r) { return f[n] * inv[r] % mod * inv[n - r] % mod; }

int main ()
{
	cin.tie(0)->sync_with_stdio(false);

	f[0] = 1; for (lol i = 1; i < N; i++) f[i] = f[i - 1] * i % mod;
	inv[N - 1] = Inv(f[N - 1]); for (lol i = N; --i;) inv[i - 1] = inv[i] * i % mod;

	cin>> n >> r;
	for (ll v, u, i = 1; i < n; i++) {
		cin>> v >> u;
		adj[v].push_back(u); adj[u].push_back(v);
	}

	DFS();
	seg.r = n; seg.build();
	seg.upd(tin[1], tout[1]);
	c[1] = r; sz[1] = n;
	fen.add(tin[1], c[1]);
	fen2.add(tin[1], sz[1]);
	ans = nCr(c[1] + sz[1] - 1, sz[1] - 1);
	cout<< ans << '\n';

	cin>> q;
	for (ll tp, v; q--;) {
		cin>> tp >> v;
		if (tp == 1) {
			cin>> c[v];
			c[v] -= fen.ask(tin[v], tout[v]);
			ll par = rtin[seg.ask(tin[v], tout[v])];
			
			if (c[par] >= 0) (ans *= Inv(nCr(c[par] + sz[par] - 1, sz[par] - 1))) %= mod;
			else zero--;

			sz[v] = tout[v] - tin[v] + 1 - fen2.ask(tin[v], tout[v]);
			sz[par] -= sz[v];
			fen2.add(tin[par], -sz[v]);
			fen2.add(tin[v], sz[v]);
			c[par] -= c[v];
			fen.add(tin[par], -c[v]);
			fen.add(tin[v], c[v]);
			
			if (c[par] >= 0) (ans *= nCr(c[par] + sz[par] - 1, sz[par] - 1)) %= mod;
			else zero++;

			if (c[v] >= 0) (ans *= nCr(c[v] + sz[v] - 1, sz[v] - 1)) %= mod;
			else zero++;

			seg.upd(tin[v], tout[v]);
		} else {
			seg.upd(tin[v], 0);
			ll par = rtin[seg.ask(tin[v], tout[v])];
			
			if (c[par] >= 0) (ans *= Inv(nCr(c[par] + sz[par] - 1, sz[par] - 1))) %= mod;
			else zero--;

			if (c[v] >= 0) (ans *= Inv(nCr(c[v] + sz[v] - 1, sz[v] - 1))) %= mod;
			else zero--;

			sz[par] += sz[v];
			fen2.add(tin[par], sz[v]);
			fen2.add(tin[v], -sz[v]);
			c[par] += c[v];
			fen.add(tin[par], c[v]);
			fen.add(tin[v], -c[v]);
			
			if (c[v] >= 0) (ans *= nCr(c[par] + sz[par] - 1, sz[par] - 1)) %= mod;
			else zero++;
		}

		cout<< (zero ? 0LL : ans) << '\n';
	}

	cerr<< "\n" __TIMESTAMP__ " - Time elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";

	return 0;
}
/*
3 2
1 2
2 3
2
1 2 1
2 2

*/

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