Submission #680764

#	Time	Username	Problem	Language	Result	Execution time	Memory
680764		arnold518	Jail (JOI22_jail)	C++17	72 / 100	5060 ms	418704 KiB

jail

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

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 2e5;

int Q, N, M;
vector<int> adj[MAXN+10];
pii A[MAXN+10];
vector<int> S[MAXN+10], E[MAXN+10];
int dep[MAXN+10], par[MAXN+10];

vector<int> adj2[MAXN+10];

void dfs(int now, int bef, int d)
{
	dep[now]=d;
	par[now]=bef;
	for(int nxt : adj[now])
	{
		if(nxt==bef) continue;
		dfs(nxt, now, d+1);
	}
}

int vis[MAXN+10];
bool dfs2(int now)
{
	vis[now]=1;
	for(int nxt : adj2[now])
	{
		if(vis[nxt]==1) return true;
		if(vis[nxt]==0 && dfs2(nxt)) return true;
	}
	vis[now]=2;
	return false;
}

bool solve()
{
	scanf("%d", &N);
	for(int i=1; i<N; i++)
	{
		int u, v;
		scanf("%d%d", &u, &v);
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	scanf("%d", &M);
	for(int i=1; i<=M; i++)
	{
		scanf("%d%d", &A[i].first, &A[i].second);
		S[A[i].first].push_back(i);
		E[A[i].second].push_back(i);
	}

	dfs(1, 0, 1);

	for(int i=1; i<=M; i++)
	{
		int u=A[i].first, v=A[i].second;
		while(1)
		{
			if(dep[u]>dep[v]) swap(u, v);
			for(auto it : S[v]) if(it!=i) adj2[it].push_back(i);
			for(auto it : E[v]) if(it!=i) adj2[i].push_back(it);
			if(u==v) break;
			v=par[v];
		}
	}

	for(int i=1; i<=M; i++)
	{
		if(vis[i]) continue;
		if(dfs2(i)) return false;
	}
	return true;
}

void clear()
{
	for(int i=1; i<=N; i++)
	{
		adj[i].clear();
		S[i].clear(); E[i].clear();
	}
	for(int i=1; i<=M; i++)
	{
		adj2[i].clear();
		vis[i]=0;
	}
}

int main()
{
	scanf("%d", &Q);
	while(Q--)
	{
		if(solve()) printf("Yes\n");
		else printf("No\n");
		clear();
	}
}

Compilation message (stderr)

jail.cpp: In function 'bool solve()':
jail.cpp:44:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |  scanf("%d", &N);
      |  ~~~~~^~~~~~~~~~
jail.cpp:48:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |   scanf("%d%d", &u, &v);
      |   ~~~~~^~~~~~~~~~~~~~~~
jail.cpp:52:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |  scanf("%d", &M);
      |  ~~~~~^~~~~~~~~~
jail.cpp:55:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   55 |   scanf("%d%d", &A[i].first, &A[i].second);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
jail.cpp: In function 'int main()':
jail.cpp:99:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |  scanf("%d", &Q);
      |  ~~~~~^~~~~~~~~~

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