Submission #977777

#	Time	Username	Problem	Language	Result	Execution time	Memory
977777		OAleksa	Spring cleaning (CEOI20_cleaning)	C++14	35 / 100	1051 ms	20564 KiB

cleaning

#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
const int N = 1e5 + 69;
const int K = 17;
pair<int, int> st[4 * N];
int n, q, ch[N], par[N], leaf[N], is[N], dep[N];
int tin[N], timer, top[N], sz[N], lzy[N];
vector<int> g[N];
void push(int v) {
	if (lzy[v] % 2 == 1) {
		lzy[v * 2] += lzy[v];
		lzy[v * 2 + 1] += lzy[v];
		swap(st[v * 2].f, st[v * 2].s);
		swap(st[v * 2 + 1].f, st[v * 2 + 1].s);
		lzy[v] = 0;
	}
}
void dfs(int v, int p) {
	par[v] = p;
	sz[v] = 1;
	if (g[v].size() == 1)
		leaf[v] = ch[v] = is[v] = 1;
	for (auto u : g[v]) {
		if (u == p)
			continue;
		dep[u] = dep[v] + 1;
		dfs(u, v);
		ch[v] += ch[u];
		sz[v] += sz[u];
	}
}
void modify(int v, int tl, int tr, int p, int x) {
	if (tl == tr) {
		if (x % 2 == 0)
			st[v] = {0, 1};
		else
			st[v] = {1, 0};
	}
	else {
		int mid = (tl + tr) / 2;
		if (p <= mid)
			modify(v * 2, tl, mid, p, x);
		else
			modify(v * 2 + 1, mid + 1, tr, p, x);
		st[v] = {st[v * 2].f + st[v * 2 + 1].f, st[v * 2].s + st[v * 2 + 1].s};
	}
}
void svapuj(int v, int tl, int tr, int l, int r) {
	if (tl > r || tr < l)
		return;
	else if (tl >= l && tr <= r) {
		lzy[v]++;
		swap(st[v].f, st[v].s);
	}
	else {
		push(v);
		int mid = (tl + tr) / 2;
		svapuj(v * 2, tl, mid, l, r);
		svapuj(v * 2 + 1, mid + 1, tr, l, r);
		st[v] = {st[v * 2].f + st[v * 2 + 1].f, st[v * 2].s + st[v * 2 + 1].s};
	}
}
pair<int, int> get(int v, int tl, int tr, int l, int r) {
	if (tl > r || tr < l)
		return {0, 0};
	else if (tl >= l && tr <= r)
		return st[v];
	else {
		int mid = (tl + tr) / 2;
		push(v);
		auto ll = get(v * 2, tl, mid, l, r);
		auto rr = get(v * 2 + 1, mid + 1, tr, l, r);
		pair<int, int> res;
		res.f = {ll.f + rr.f};
		res.s = {ll.s + rr.s};
		return res;
	}
}
void hld(int v, int p, int tp) {
	int s = -1;
	tin[v] = ++timer;
	top[v] = tp;
	modify(1, 1, n, tin[v], ch[v]);
	for (auto u : g[v]) {
		if (u == p)
			continue;
		if (s == -1 || sz[s] < sz[u])
			s = u;
	}
	if (s != -1)
		hld(s, v, tp);
	for (auto u : g[v]) {
		if (u == p || u == s)
			continue;
		hld(u, v, u);
	}
}
signed main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> q;
	for (int i = 1;i <= n - 1;i++) {
		int a, b;
		cin >> a >> b;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	dfs(1, 0);
	hld(1, 0, 1);
	int uk = ch[1];
	while (q--) {
		int t;
		cin >> t;
		int a[t];
		for (int i = 0;i < t;i++) {
			cin >> a[i];
			int v = a[i];
			uk++;
			if (leaf[v]) {
				leaf[v]--;
				uk--;
				int v = a[i];
				while (v > 0) {
					svapuj(1, 1, n, tin[top[v]], tin[v]);
					v = par[top[v]];
				}
			}
			v = a[i];
			while (v > 0) {
				svapuj(1, 1, n, tin[top[v]], tin[v]);
				v = par[top[v]];
			}
		}
		if (uk % 2 == 1)
			cout << "-1\n";
		else {
			pair<int, int> res;
			res = get(1, 1, n, 2, n);
			cout << res.f + 2 * res.s + t << '\n';
		}
		for (int i = 0;i < t;i++) {
			uk--;
			int v = a[i];
			if (is[a[i]] && !leaf[a[i]]) {
				uk++;
				leaf[a[i]] = 1;
				while (v > 0) {
					svapuj(1, 1, n, tin[top[v]], tin[v]);
					v = par[top[v]];
				}
			}
			v = a[i];
			while (v > 0) {
				svapuj(1, 1, n, tin[top[v]], tin[v]);
				v = par[top[v]];
			}
		}
	}
	return 0;
}

• Subtask 1: 0 / 0
• Subtask 2: 0 / 9
• Subtask 3: 0 / 9
• Subtask 4: 16 / 16
• Subtask 5: 19 / 19
• Subtask 6: 0 / 17
• Subtask 7: 0 / 30