Submission #780638

#	Time	Username	Problem	Language	Result	Execution time	Memory
780638		Sami_Massah	Sumtree (INOI20_sumtree)	C++17	100 / 100	2217 ms	307616 KiB

Main

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


const int maxn = 5e5 + 12, maxk = 2e5 + 12, lg = 18, mod = 1e9 + 7;
int n, bs, tz, tms, h[maxk], col[maxk], par[maxk][lg], sz[maxk], st[maxk], en[maxk], L[maxk * 3], R[maxk * 3], sum1[maxk * 3], sum2[maxk * 3];
long long ans, fact[maxn], rfact[maxn];
set <pair<int, int>> Q[maxk * 3];
vector <int> conn[maxk];
bitset <maxn> marked, zero;
long long tav(long long a, long long b){
    if(b == 0)
        return 1;
    a %= mod;
    long long x = tav(a * a % mod, b / 2);
    if(b % 2)
        return x * a % mod;
    return x % mod;
}
void make_tree(int l, int r, int ind){
    int mid = (l + r) / 2;
    L[ind] = l;
    R[ind] = r;
    if(l == r)
        return;
    make_tree(l, mid, ind * 2);
    make_tree(mid + 1, r, ind * 2 + 1);
}
void update_tree1(int l, int r, int u, int k){
    if(r < L[u] || R[u] < l)
        return;
    if(l <= L[u] && R[u] <= r){
        sum1[u] = k;
        return;
    }
    update_tree1(l, r, u * 2, k);
    update_tree1(l, r, u * 2 + 1, k);
    sum1[u] = sum1[u * 2] + sum1[u * 2 + 1];
}
void update_tree2(int l, int r, int u, int k){
    if(r < L[u] || R[u] < l)
        return;
    if(l <= L[u] && R[u] <= r){
        sum2[u] = k;
        return;
    }
    update_tree2(l, r, u * 2, k);
    update_tree2(l, r, u * 2 + 1, k);
    sum2[u] = sum2[u * 2] + sum2[u * 2 + 1];
}
int get_sum1(int l, int r, int u){
    if(r < L[u] || R[u] < l)
        return 0;
    if(l <= L[u] && R[u] <= r)
        return sum1[u];
    return get_sum1(l, r, u * 2) + get_sum1(l, r, u * 2 + 1);
}
int get_sum2(int l, int r, int u){
    if(r < L[u] || R[u] < l)
        return 0;
    if(l <= L[u] && R[u] <= r)
        return sum2[u];
    return get_sum2(l, r, u * 2) + get_sum2(l, r, u * 2 + 1);
}
void dfs_set(int u){
    marked[u] = 1;
    sz[u] = 1;
    st[u] = tms;
    tms += 1;
    for(int i = 0; i + 1 < lg; i++)
        par[u][i + 1] = par[par[u][i]][i];
    for(int v: conn[u])
        if(!marked[v]){
            par[v][0] = u;
            h[v] = h[u] + 1;
            dfs_set(v);
            sz[u] += sz[v];

        }
    en[u] = tms - 1;
}
void add_to_tree(int l, int r, int u, int k){
    if(r < L[u] || R[u] < l)
        return;
    if(l <= L[u] && R[u] <= r){
        Q[u].insert(make_pair(h[k], k));
        return;
    }
    add_to_tree(l, r, u * 2, k);
    add_to_tree(l, r, u * 2 + 1, k);
}
void erase_from_tree(int l, int r, int u, int k){
    if(r < L[u] || R[u] < l)
        return;
    if(l <= L[u] && R[u] <= r){
        Q[u].erase(make_pair(h[k], k));
        return;
    }
    erase_from_tree(l, r, u * 2, k);
    erase_from_tree(l, r, u * 2 + 1, k);
}
pair<int, int> find_pd(int l, int r, int u){
    if(r < L[u] || R[u] < l)
        return make_pair(-1, 0);
    if(l <= L[u] && R[u] <= r){
        if(Q[u].size() == 0)
            return make_pair(-1, 0);
        return *Q[u].rbegin();
    }
    auto x = make_pair(-1, 0);
    if(Q[u].size())
        x = *Q[u].rbegin();
    return max({find_pd(l, r, u * 2), find_pd(l, r, u * 2 + 1), x});
}
long long get_c(int a, int b){
    if(a < b)
        return 0;
    return fact[a] * (rfact[b] * rfact[a - b] % mod) % mod;

}
void add_tree(int u, int k){
    int pd = find_pd(st[u], st[u], 1).second;
 //   cout << u << ' ' << pd << endl;
   // cout << u << ' ' << pd << endl;
    col[u] = k;
    if(u != 1){
        int x = get_sum1(st[pd] + 1, en[pd], 1);
        int d = get_sum2(st[pd] + 1, en[pd], 1);

        if(zero[pd] == 0){
            x = sz[pd] - x;
            d = col[pd] - d;
            long long f = get_c(d + x - 1, x - 1);
            ans = ans * tav(f, mod - 2) % mod;
        }
    }
  //  cout << ans << endl;
    int x = get_sum1(st[u], en[u], 1);
    int d = get_sum2(st[u], en[u], 1);
    update_tree1(st[u], st[u], 1, sz[u] - x);
    update_tree2(st[u], st[u], 1, k - d);
    add_to_tree(st[u] + 1, en[u], 1, u);
   // cout << st[pd] << '-' << en[pd] << endl;
    if(k < d){
        zero[u] = 1;
        tz += 1;
    }
    else{
 //       cout << x << ' ' << sz[u] << endl;
        x = sz[u] - x;
        d = k - d;
      //  cout << x << ' ' << d << endl;
        long long f = get_c(d + x - 1, x - 1);
        ans = ans * f % mod;
    }
   // cout << ans << endl;

    if(u != 1){
        int x = get_sum1(st[pd] + 1, en[pd], 1);
        int d = get_sum2(st[pd] + 1, en[pd], 1);
        update_tree1(st[pd], st[pd], 1, sz[pd] - x);
        update_tree2(st[pd], st[pd], 1, col[pd] - d);
        if(col[pd] < d){
            tz += (1 - zero[pd]);
            zero[pd] = 1;
        }
        else{
            x = sz[pd] - x;
            d = col[pd] - d;
            tz -= zero[pd];
            zero[pd] = 0;
    //        cout << x << ' ' << d << endl;
            long long f = get_c(d + x - 1, x - 1);
            ans = ans * f % mod;
        }
    }
    //cout << ans << endl << endl;
}
void remove_tree(int u){

    int pd = find_pd(st[u], st[u], 1).second;
   // cout << u << ' ' << pd << endl;
    int x = get_sum1(st[pd] + 1, en[pd], 1);
    int d = get_sum2(st[pd] + 1, en[pd], 1);

    if(zero[pd] == 0){
        x = sz[pd] - x;
        d = col[pd] - d;
        long long f = get_c(d + x - 1, x - 1);
        ans = ans * tav(f, mod - 2) % mod;
    }

    x = get_sum1(st[u] + 1, en[u], 1);
    d = get_sum2(st[u] + 1, en[u], 1);

    update_tree1(st[u], st[u], 1, 0);
    update_tree2(st[u], st[u], 1, 0);
    erase_from_tree(st[u] + 1, en[u], 1, u);
    //cout << get_sum1(1, n, 1) << endl;
    if(col[u] < d){
        tz -= zero[u];
        zero[u] = 0;
    }
    else{
        tz -= zero[u];
        zero[u] = 0;
        x = sz[u] - x;
        d = col[u] - d;
    //    cout << d << ' ' << x << endl;
        long long f = get_c(d + x - 1, x - 1);
        ans = ans * tav(f, mod - 2) % mod;
    }
    col[u] = -1;


    x = get_sum1(st[pd] + 1, en[pd], 1);
    d = get_sum2(st[pd] + 1, en[pd], 1);

    update_tree1(st[pd], st[pd], 1, sz[pd] - x);
    update_tree2(st[pd], st[pd], 1, col[pd] - d);

    if(col[pd] < d){
        tz += (1 - zero[pd]);
        zero[pd] = 1;
    }
    else{
        tz -= (zero[pd]);
        zero[pd] = 0;
        x = sz[pd] - x;
        d = col[pd] - d;
      //  cout << d << ' ' << x << endl;
        long long f = get_c(d + x - 1, x - 1);
        ans = ans * f % mod;
    }
}
int main(){
    ios_base::sync_with_stdio(false), cin.tie(0);
    memset(col, -1, sizeof col);
    col[0] = 0;
    fact[0] = 1;
    for(int i = 1; i < maxn; i++)
        fact[i] = fact[i - 1] * i % mod;
    for(int i = 0; i < maxn; i++)
        rfact[i] = tav(fact[i], mod - 2) % mod;
    cin >> n >> bs;
    for(int i = 0; i < n - 1; i++){
        int a, b;
        cin >> a >> b;
        conn[a].push_back(b);
        conn[b].push_back(a);
    }
    cout << endl;
    dfs_set(1);
    make_tree(0, n, 1);
    ans = 1;
    add_tree(1, bs);
    cout << ans << "\n";
    int q;
    cin >> q;
    for(int i = 0; i < q; i++){
        int a;
        int b, c;
        cin >> a;
        if(a == 1){
            cin >> b >> c;
            add_tree(b, c);
        }
        else{
            cin >> b;
            remove_tree(b);
        }
        if(tz)
            cout << 0 << "\n";
        else
            cout << ans << "\n";

    }





}

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