Submission #872602

#	Time	Username	Problem	Language	Result	Execution time	Memory
872602		vjudge1	Ball Machine (BOI13_ballmachine)	C++17	89.39 / 100	847 ms	54752 KiB

ballmachine

#include<bits/stdc++.h>
using namespace std;
 
#define int long long
#define F first
#define S second
#define pii pair<int, int>
#define pb push_back
#define pp pop_back
#define all(x) x.begin(), x.end()
 
const int N = 1e5 + 12, M = 20;
vector<int> g[N];
int n, q, t, f[N], p[N], par[M][N], root, d[N], seg[4 * N], lazy[4 * N], ls[4 * N], h[N];
pii pl[4 * N];
 
void ip() {
	cin >> n >> q;
	for (int i = 0; i < n; i++) {
		int u;
		cin >> u;
		u--;
		par[0][i] = u;
		if (u == -1)
			root = i;
		else {
			g[u].pb(i);
			g[i].pb(u);
		}
	}
	par[0][root] = root;
}
 
void dfs1(int u) {
	d[u] = u;
	for (auto i: g[u])
		if (i != par[0][u]) {
			h[i] = h[u] + 1;
			dfs1(i);
			d[u] = min(d[u], d[i]);
		}
}
 
void dfs2(int u) {
	vector<pii> tmp;
	for (auto i: g[u])
		if (i != par[0][u])
			tmp.pb({d[i], i});
	sort(all(tmp));
	for (auto i: tmp)
		dfs2(i.S);
	f[t] = u;
	p[u] = t;
	t++;
}
 
void pre() {
	dfs1(root);
	dfs2(root);
	for (int i = 1; i < M; i++)
		for (int j = 0; j < n; j++)
			par[i][j] = par[i - 1][par[i - 1][j]];
}
 
void shift(int id) {
	if (ls[id * 2] < ls[id]) {
		seg[id * 2] = lazy[id] * (pl[id * 2].S - pl[id * 2].F);
		lazy[id * 2] = lazy[id];
		ls[id * 2] = ls[id];
	}
	if (ls[id * 2 + 1] < ls[id]) {
		lazy[id * 2 + 1] = lazy[id];
		seg[id * 2 + 1] = lazy[id] * (pl[id * 2 + 1].S - pl[id * 2 + 1].F); 
		ls[id * 2 + 1] = ls[id];
	}
}
 
void add(int l, int r, int x, int w, int id = 1) {
	if (l <= pl[id].F && r >= pl[id].S) {
		lazy[id] = x;
		seg[id] = x * (pl[id].S - pl[id].F);
		ls[id] = w;
		return;
	}
	if (r <= pl[id].F || l >= pl[id].S) 
		return;
	shift(id);
	add(l, r, x, w, id * 2);
	add(l, r, x, w, id * 2 + 1);
	seg[id] = seg[id * 2] + seg[id * 2 + 1];
}
 
int ask(int l, int r, int id = 1) {
	if (l <= pl[id].F && r >= pl[id].S) 
		return seg[id];
	if (r <= pl[id].F || l >= pl[id].S) 
		return 0;
	shift(id);
	int res = ask(l, r, id * 2) + ask(l, r, id * 2 + 1);
	seg[id] = seg[id * 2] + seg[id * 2 + 1];
	return res;
}
 
void query() {
	int w = 1;
	pl[1] = {0, n};
	for (int i = 1; i < 2 * n; i++) {
		int mid = (pl[i].F + pl[i].S) / 2;
		pl[i * 2] = {pl[i].F, mid};
		pl[i * 2 + 1] = {mid, pl[i].S};
	}
	while (q--) {
		int u, v;
		cin >> u >> v;
		if (u == 1) {
			int l = -1, r = n;
			while (r - l > 1) {
				int mid = (l + r) / 2;
				if (mid + 1 - ask(0, mid + 1) <= v)
					l = mid;
				else
					r = mid;
			}
			cout << f[l] + 1 << '\n';
			add(0, l + 1, 1, w++);
		}
		else {
			v--;
			int z = v;
			for (int i = M - 1; ~i; i--)
				if (ask(p[par[i][v]], p[par[i][v]] + 1))
					v = par[i][v];
			cout << h[z] - h[v] << '\n';
			add(p[v], p[v] + 1, 0, w++);
		}
	}
}
 
int32_t main() {
	ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	ip(), pre(), query();
	return 0;
}

• Subtask 1: 19.23076923076923 / 25
• Subtask 2: 25.714285714285715 / 30
• Subtask 3: 40 / 40
• Subtask 4: 4.444444444444445 / 5