Submission #1293255

#	Time	Username	Problem	Language	Result	Execution time	Memory
1293255		thdh__	Sumtree (INOI20_sumtree)	C++20	100 / 100	939 ms	96912 KiB

Main

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define eb emplace_back
#define pu push
#define ins insert
#define fi first
#define se second
#define all(a) a.begin(),a.end()
#define bruh ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fu(x,a,b) for (auto x=a;x<=b;x++)
#define fd(x,a,b) for (auto x=a;x>=b;x--)
#define int ll

using namespace std;
//mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());

/*
Competitive Programming notes that I need to study & fix my dumbass self:

1. Coding:
- Always be sure to check the memory of arrays (maybe use vectors), for loops
- Always try to maximize the memory if possible, even if you are going for subtasks
- Do not exploit #define int long long, it will kill you

2. Stress: 
- Always try generating big testcases and try if they run

3. Time management:
- Don't overcommit or undercommit, always spend a certain amount of time to think a problem, don't just look at it and say I'm fucked
- Do not spend too much time coding brute-force solutions, they should be easily-codable solutions that don't take up too much time

Time management schedule:
Offline / LAH days (4 problems - 3h):
15' thinking of solution / idea
1. no idea: skip
2. yes idea: continue thinking for <= 15'

+ implementing: <= 20'
+ brute-force: <= 5'
+ test generator: <= 5'

I hate offline because I am dumb
*/

typedef pair<int, int> ii;
const int N = 1e6+5;
const int B = 750;
const int mod = 1e9+7;
const int inf = 1e18;
using cd = complex<double>;
const long double PI = acos(-1);
int power(int a,int b) {ll x = 1;if (a >= mod) a%=mod; while (b) {if (b & 1) x = x*a % mod;a = a*a % mod;b>>=1;}return x;} 

int gt[N], inv[N];

void precalc() 
{
	gt[0] = 1;
	for (int i = 1; i < N; i++) gt[i] = (gt[i-1] * i) % mod;
	inv[N-1] = power(gt[N-1], mod-2);
	for (int i = N-2; i >= 0; i--) inv[i] = (inv[i+1] * (i+1)) % mod;
}

int C(int n, int k) 
{
	if (k > n) return 0;
	if (k == n || !k) return 1;
	return (gt[n] * inv[k] % mod) * inv[n-k] % mod;
}

int calc(int n, int r) 
{
    return C(n+r-1, n-1);
}

// Position ST (find the first parent node that is on) 

int stp[4*N];

void updatep(int id, int l, int r, int i, int val) 
{
    if (l == r) 
    {
        stp[id] = val;
        return;
    }
    int mid = l+r>>1;
    if (i <= mid) updatep(id*2, l, mid, i, val);
    else updatep(id*2+1, mid+1, r, i, val);
    if (stp[id*2+1] != -1) stp[id] = stp[id*2+1];
    else stp[id] = stp[id*2];
}

int getp(int id, int l, int r, int u, int v) 
{
    if (l > v || r < u) return -1;
    if (u <= l && r <= v) return stp[id];
    int mid = l+r>>1;
    int le = getp(id*2, l, mid, u, v), ri = getp(id*2+1, mid+1, r, u, v);
    if (ri != -1) return ri;
    else return le;
}

// ST sum of sizes

int stsz[4*N];

void updatesz(int id, int l, int r, int i, int val) 
{
    if (l == r) 
    {
        stsz[id] = val;
        return;
    }
    int mid = l+r>>1;
    if (i <= mid) updatesz(id*2, l, mid, i, val);
    else updatesz(id*2+1, mid+1, r, i, val);
    stsz[id] = stsz[id*2] + stsz[id*2+1];
}

int getsz(int id, int l, int r, int u, int v) 
{
    if (l > v || r < u) return 0;
    if (u <= l && r <= v) return stsz[id];
    int mid = l+r>>1;
    return getsz(id*2, l, mid, u, v) + getsz(id*2+1, mid+1, r, u, v);
}

// ST sum of values

int stv[4*N];

void updatev(int id, int l, int r, int i, int val) 
{
    if (l == r) 
    {
        stv[id] = val;
        return;
    }
    int mid = l+r>>1;
    if (i <= mid) updatev(id*2, l, mid, i, val);
    else updatev(id*2+1, mid+1, r, i, val);
    stv[id] = stv[id*2] + stv[id*2+1];
}

int getv(int id, int l, int r, int u, int v) 
{
    if (l > v || r < u) return 0;
    if (u <= l && r <= v) return stv[id];
    int mid = l+r>>1;
    return getv(id*2, l, mid, u, v) + getv(id*2+1, mid+1, r, u, v);
}

int n,r,q;
int a[N], c[N], cnt[N], vl[N];
vector<int> adj[N];
int ans, z = 0;

// HLD

int sz[N], heavy[N], head[N], tin[N], tout[N], timer = 0, par[N];

void predfs(int u, int p) 
{
    par[u] = p;
    sz[u] = 1;
    for (auto v : adj[u]) 
    {
        if (v == p) continue;
        predfs(v, u);
        sz[u] += sz[v];
        if (sz[v] > sz[heavy[u]]) heavy[u] = v;
    }
}

void decompose(int u, int p) 
{
    head[u] = p;
    tin[u] = ++timer;
    if (heavy[u]) decompose(heavy[u], p);
    for (auto v : adj[u]) 
    {
        if (v == par[u] || v == heavy[u]) continue;
        decompose(v, v);
    }
    tout[u] = timer;
}

int up(int u) // find nearest "on" parent
{
    int pos = -1;
    while (u) 
    {
        int tmp = getp(1, 1, n, tin[head[u]], tin[u]);
        if (tmp != -1) 
        {
            pos = tmp;
            break;
        }
        u = par[head[u]];
    }
    return pos;
}

void add(int u, int val) 
{
    a[u] = val;
    int x = up(u);
    if (c[x]) ans = (ans * power(c[x], mod-2)) % mod;
    else z--;
    vl[u] = val - getv(1, 1, n, tin[u], tout[u]);
    cnt[u] = sz[u] - getsz(1, 1, n, tin[u], tout[u]);
    vl[x] -= vl[u];
    cnt[x] -= cnt[u];
    // cout<<u<<" "<<x<<endl;
    // cout<<vl[u]<<" "<<cnt[u]<<" "<<vl[x]<<" "<<cnt[x]<<endl;
    updatev(1, 1, n, tin[u], vl[u]); updatev(1, 1, n, tin[x], vl[x]);
    updatesz(1, 1, n, tin[u], cnt[u]); updatesz(1, 1, n, tin[x], cnt[x]);
    updatep(1, 1, n, tin[u], u);
    c[u] = calc(cnt[u], vl[u]);
    c[x] = calc(cnt[x], vl[x]);
    if (c[u]) ans = (ans * c[u]) % mod;
    else z++;
    if (c[x]) ans = (ans * c[x]) % mod;
    else z++;
}
 
void del(int u) 
{
    int x = up(par[u]);
    if (c[x]) ans = (ans * power(c[x], mod-2)) % mod;
    else z--;
    if (c[u]) ans = (ans * power(c[u], mod-2)) % mod;
    else z--;
    vl[x] += vl[u]; 
    cnt[x] += cnt[u];
    vl[u] = cnt[u] = c[u] = 0;
    updatev(1, 1, n, tin[u], vl[u]); updatev(1, 1, n, tin[x], vl[x]);
    updatesz(1, 1, n, tin[u], cnt[u]); updatesz(1, 1, n, tin[x], cnt[x]);
    updatep(1, 1, n, tin[u], -1);
    c[x] = calc(cnt[x], vl[x]);
    if (c[x]) ans = (ans * c[x]) % mod;
    else z++;
    a[u] = -1;
}

void solve()
{
    memset(stp, -1, sizeof(stp));
	precalc();
	cin>>n>>r;
	for (int i = 1; i < n; i++) 
	{
		int u,v;
		cin>>u>>v;
		adj[u].pb(v); adj[v].pb(u);
	}
	if (n == 1) 
	{
		cout<<1<<endl;
		cin>>q;
		while (q--) 
		{
			cout<<1<<endl;
		}
		return;
	}
    for (int i = 1; i <= n; i++) a[i] = -1;
    a[1] = r;
	ans = c[1] = calc(n, r);
    cnt[1] = n;
    vl[1] = r;
    updatesz(1, 1, n, 1, cnt[1]);
    updatev(1, 1, n, 1, vl[1]);
    updatep(1, 1, n, 1, 1);
	cout<<ans<<endl;
    predfs(1, 0);
    decompose(1, 1);
	cin>>q;
	while (q--) 
	{
		int tp, u;
		cin>>tp>>u;
		if (tp == 1) 
		{
			int v; cin>>v;
            add(u, v);
		} else del(u);
		if (!z) cout<<ans<<endl;
        else cout<<0<<endl;
	}
}

/*
Go through the mistakes you usually make and revise your code, for god's sake...
*/

signed main()
{
	bruh
	//freopen(".inp","r",stdin);
	//freopen(".out","w",stdout);
	int t = 1;
	// cin>>t;
	while (t--)
	{
		solve();
		cout<<"\n";
	}
}

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