Submission #726812

#	Time	Username	Problem	Language	Result	Execution time	Memory
726812		dozer	Jail (JOI22_jail)	C++14	61 / 100	5077 ms	33692 KiB

jail

#include <bits/stdc++.h>
using namespace std;
#define fastio() cin.tie(0), ios_base::sync_with_stdio(0)
#define sp " "
#define endl "\n"
#define pb push_back
#define pii pair<int, int>
#define st first
#define nd second
#define N 200005
#define LOGN 18


vector<int> adj[N], adj2[N];
int tin[N], tout[N], s[N], t[N], par[LOGN][N];
int cntr, dep[N], deg[N];


void dfs(int node, int root, int d)
{
	tin[node] = cntr++;
	dep[node] = d;
	par[0][node] = root;
	for (auto i : adj[node])
		if (i != root) dfs(i, node, d + 1);
	tout[node] = cntr++;
}

bool ancestor(int a, int b)
{
	return (tin[a] <= tin[b] && tout[a] >= tout[b]);
}

int lca(int a, int b)
{
	for (int i = LOGN - 1; i >= 0; i--)
	{
		if ((1<<i) < dep[a] && !ancestor(par[i][a], b)) a = par[i][a];
	}
	if (!ancestor(a, b)) a = par[0][a];
	return a;
}

bool intersects(int x, int a, int b)
{
	int l = lca(a, b);
	if (x == l) return 1;
	return (ancestor(x, a) ^ ancestor(x, b));
}


int32_t main()
{
	fastio();


	int q;
	cin>>q;
	while(q--)
	{
		int n, m;
		cin>>n;
		for (int i = 1; i <= n; i++)
			adj[i].clear();
		for (int i = 1; i < n; i++)
		{
			int u, v;
			cin>>u>>v;
			adj[u].pb(v);
			adj[v].pb(u);
		}

		cntr = 0;
		dfs(1, 0, 0);
		for (int i = 1; i < LOGN; i++)
		{
			for (int j = 1; j <= n; j++)
				par[i][j] = par[i - 1][par[i - 1][j]];
		}
		vector<pii> v;
		cin>>m;
		for (int i = 1; i <= m; i++)
			adj2[i].clear(), deg[i] = 0;

		for (int i = 1; i <= m; i++)
			cin>>s[i]>>t[i];

		for (int i = 1; i <= m; i++)
		{
			for (int j = i + 1; j <= m; j++)
			{
				if (intersects(s[i], s[j], t[j]) || intersects(t[j], s[i], t[i])) adj2[i].pb(j), deg[j]++;
				if (intersects(t[i], s[j], t[j]) || intersects(s[j], s[i], t[i])) adj2[j].pb(i), deg[i]++;
			}
		}

		vector<int> done(m + 5, 0);

		queue<int> q;
		for (int i = 1; i <= m; i++)
			if (deg[i] == 0) q.push(i);

		while(!q.empty())
		{
			int top = q.front();
			q.pop();
			done[top] = 1;
			for (auto i : adj2[top])
			{
				deg[i]--;
				if (deg[i] == 0) q.push(i);
			}
		} 

		int flag = 1;
		for (int i = 1; i <= m; i++)
		{
			flag &= done[i];
		}

		if (flag) cout<<"Yes\n";
		else cout<<"No\n";

	}

	cerr<<"time taken : "<<(float)clock() / CLOCKS_PER_SEC<<" seconds\n";
}

• 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