Submission #884985

#	Time	Username	Problem	Language	Result	Execution time	Memory
884985		MinaRagy06	Jail (JOI22_jail)	C++17	61 / 100	5070 ms	25556 KiB

jail

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

const int N = 120'005;
vector<int> adj[N];
int st[N], en[N], h[N], anc[N][17], t;
void dfs(int i, int par, int d = 0) {
	anc[i][0] = par;
	for (int j = 1; j < 17; j++) {
		anc[i][j] = anc[anc[i][j - 1]][j - 1];
	}
	h[i] = d;
	st[i] = t++;
	for (auto nxt : adj[i]) {
		if (nxt == par) continue;
		dfs(nxt, i, d + 1);
	}
	en[i] = t - 1;
}
int getlca(int u, int v) {
	if (st[u] <= st[v] && en[v] <= en[u]) {
		return u;
	}
	for (int j = 16; j >= 0; j--) {
		int nxtu = anc[u][j];
		if (!(st[nxtu] <= st[v] && en[v] <= en[nxtu])) {
			u = nxtu;
		}
	}
	return anc[u][0];
}
struct path {
	int s, e, lca;
} a[N];
int m;
bool vis[N], instack[N];
bool dfs2(int i) {
	vis[i] = 1;
	instack[i] = 1;
	bool ok = 1;
// 	cout << i + 1 << '\n';
	for (int j = 0; j < m; j++) {
		if (j == i) continue;
		bool gud = st[a[i].lca] <= st[a[j].s] && st[a[j].s] <= st[a[i].s] && st[a[i].s] <= en[a[j].s];
		gud |= st[a[i].lca] <= st[a[j].s] && st[a[j].s] <= st[a[i].e] && st[a[i].e] <= en[a[j].s];	
		gud |= st[a[i].e] <= st[a[j].s] && st[a[j].s] <= en[a[i].e] && st[a[j].lca] <= st[a[i].e];
		gud |= st[a[i].e] <= st[a[j].e] && st[a[j].e] <= en[a[i].e] && st[a[j].lca] <= st[a[i].e]; 
		if (gud) {
			if (instack[j]) {
				ok = 0;
				break;
			}
			if (vis[j]) continue;
			if (!dfs2(j)) {
				ok = 0;
				break;
			}
		}
	}
	instack[i] = 0;
	return ok;
}
int main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	int T;
	cin >> T;
	while (T--) {
		int n;
		cin >> n;
		for (int i = 0; i < n; i++) {
			adj[i].clear();
			vis[i] = 0;
			instack[i] = 0;
		}
		for (int i = 1, u, v; i < n; i++) {
			cin >> u >> v;
			u--, v--;
			adj[u].push_back(v);
			adj[v].push_back(u);
		}
		t = 0;
		dfs(0, 0);
		cin >> m;
		for (int i = 0; i < m; i++) {
			cin >> a[i].s >> a[i].e;
			a[i].s--, a[i].e--;
			a[i].lca = getlca(a[i].s, a[i].e);
// 			cout << a[i].s + 1 << ' ' << a[i].e + 1 << ' ' << a[i].lca + 1 << '\n';
		}
		auto check = [&] (int i, int x) {
			if (st[a[i].lca] <= st[x] && en[x] <= en[a[i].lca] && 
				((st[x] <= st[a[i].s] && en[a[i].s] <= en[x]) ||
				(st[x] <= st[a[i].e] && en[a[i].e] <= en[x]))) {
				return 1;
			}
			return 0;
		};
		bool ok = 1;
		for (int i = 0; i < m; i++) {
			if (vis[i]) continue;
			if (!dfs2(i)) {
				ok = 0;
			}
		}
		cout << (ok? "Yes\n" : "No\n");
	}
	return 0;
}

Compilation message (stderr)

jail.cpp: In function 'int main()':
jail.cpp:91:8: warning: variable 'check' set but not used [-Wunused-but-set-variable]
   91 |   auto check = [&] (int i, int x) {
      |        ^~~~~

• 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