제출 #1318339

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1318339		4QT0R	Sumtree (INOI20_sumtree)	C++20	50 / 100	3095 ms	36532 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define ll long long

const ll mod = 1e9 + 7;

vector<ll> graph[200003];
ll fat[200003];
ll label[200003];
bool has_label[200003];
ll label_sum[200003];
ll siz[200003];

void path_add(ll v, ll p, ll roz, ll sum)
{
    while (v != fat[p])
    {
        siz[v] += roz;
        label_sum[v] += sum;
        v = fat[v];
    }
}

void prep(ll v, ll p)
{
    fat[v] = p;
    siz[v] = 1;
    for (auto u : graph[v])
    {
        if (u == p)
            continue;
        prep(u, v);
        siz[v] += siz[u];
    }
}

ll fact[500003];
ll fact_inv[500003];

ll fast_pow(ll a, ll b)
{
    if (b == 1)
        return a;
    ll cur = fast_pow(a, b / 2);
    cur = (cur * cur) % mod;
    if (b & 1)
        cur = (cur * a) % mod;
    return cur;
}

void init(ll &n, ll &r, ll &q)
{
    cin >> n >> r;
    for (ll i = 1, a, b; i < n; i++)
    {
        cin >> a >> b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    cin >> q;

    fact[0] = 1;
    for (ll i = 1; i <= 500002; i++)
        fact[i] = (i * fact[i - 1]) % mod;
    fact_inv[500002] = fast_pow(fact[500002], mod - 2);
    for (ll i = 500001; i >= 0; i--)
        fact_inv[i] = ((i + 1) * fact_inv[i + 1]) % mod;
}

ll res(ll roz, ll tag)
{
    ll wyn = fact[roz + tag - 1];
    wyn = (wyn * fact_inv[tag]) % mod;
    wyn = (wyn * fact_inv[roz - 1]) % mod;
    return wyn;
}

ll Find(ll v)
{
    if (has_label[v])
        return v;
    return Find(fat[v]);
}

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

    ll n, q;
    init(n, label[1], q);
    has_label[1] = true;
    prep(1, 0);
    ll ans = res(n, label[1]), neg_vert = 0;
    cout << ans << '\n';
    auto modify_ans = [&](ll roz, ll lab, ll inv) -> void
    {
        if (lab < 0)
        {
            neg_vert += inv;
            return;
        }
        if (inv == 1)
            ans = (ans * res(roz, lab)) % mod;
        else
            ans = (ans * fast_pow(res(roz, lab), mod - 2)) % mod;
    };
    for (ll i = 1, t, v, tag; i <= q; i++)
    {
        cin >> t >> v;
        if (t == 1)
            cin >> tag;

        ll up = Find(fat[v]);
        modify_ans(siz[up], label[up] + label_sum[up], -1);
        if (t == 1)
        {
            has_label[v] = true;
            label[v] = tag;
            modify_ans(siz[v], label[v] + label_sum[v], 1);
            path_add(fat[v], up, -siz[v], -label[v] - label_sum[v]);
        }
        else
        {
            path_add(fat[v], up, siz[v], label[v] + label_sum[v]);
            modify_ans(siz[v], label[v] + label_sum[v], -1);
            label[v] = 0;
            has_label[v] = false;
        }
        modify_ans(siz[up], label[up] + label_sum[up], 1);

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

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