Submission #588227

#	Time	Username	Problem	Language	Result	Execution time	Memory
588227		valerikk	Jail (JOI22_jail)	C++17	61 / 100	5074 ms	32284 KiB

jail

#include <iostream>
#include <algorithm>
#include <vector>
#include <cassert>
#include <cmath>
#include <set>
#include <map>
#include <deque>
#include <queue>
#include <iomanip>

using namespace std;

#define pb push_back
#define mp make_pair
#define sz(a) ((int) (a).size())
#define all(a) (a).begin(), (a).end()

using ll = long long;

const int N = 120121;
const int K = 20;

int n;
vector<int> g[N];
int m;
int s[N], t[N];
int up[N][K];
int tin[N], tout[N], ttt;
vector<int> g1[N];
int used[N];
bool bad;

void dfs(int v, int p) {
	up[v][0] = p;
	for (int i = 1; i < K; ++i) {
		up[v][i] = up[up[v][i - 1]][i - 1];
	}
	tin[v] = ttt++;

	for (int u : g[v]) {
		if (u != p) dfs(u, v);
	}

	tout[v] = ttt;
}

bool anc(int v, int u) {
	return tin[v] <= tin[u] && tout[v] >= tout[u];
}

int get_lca(int v, int u) {
	if (anc(v, u)) return v;
	if (anc(u, v)) return u;
	for (int i = K - 1; i >= 0; --i) {
		if (!anc(up[v][i], u)) {
			v = up[v][i];
		}
	}
	return up[v][0];
}

bool on_path(int a, int b, int v) {
	int c = get_lca(a, b);

	return anc(c, v) && (anc(v, a) || anc(v, b));
}

void dfs1(int v) {
	used[v] = 1;
	for (int u : g1[v]) {
		if (used[u] == 1) bad = 1;
		if (used[u] == 0) dfs1(u);
	}
	used[v] = 2;
}

void solve() {
	cin >> n;
	for (int i = 1; i <= n; ++i) {
		g[i].clear();
	}
	for (int i = 0; i < n - 1; ++i) {
		int a, b;
		cin >> a >> b;
		g[a].pb(b);
		g[b].pb(a);
	}

	cin >> m;
	for (int i = 0; i < m; ++i) {
		cin >> s[i] >> t[i];
	}

	ttt = 0;
	dfs(1, 1);

	for (int i = 0; i < m; ++i) {
		g1[i].clear();
	}
	for (int i = 0; i < m; ++i) {
		for (int j = 0; j < m; ++j) {
			if (i == j) continue;
			if (on_path(s[i], t[i], s[j])) g1[j].pb(i);
			if (on_path(s[i], t[i], t[j])) g1[i].pb(j);
		}
	}

	for (int i = 0; i < m; ++i) {
		used[i] = 0;
	}
	bad = 0;
	for (int i = 0; i < m; ++i) {
		if (used[i] == 0) dfs1(i);
	}

	cout << (bad ? "No" : "Yes") << "\n";
}

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

	int q; 
	cin >> q;
	while (q--) {
		solve();
	}
	return 0;	
}

• Subtask 1: 0 / 5
• Subtask 2: 5 / 5
• Subtask 3: 16 / 16
• Subtask 4: 28 / 28
• Subtask 5: 12 / 12
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23