Submission #680775

#	Time	Username	Problem	Language	Result	Execution time	Memory
680775		arnold518	Jail (JOI22_jail)	C++17	0 / 100	58 ms	52084 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, NN, M;
vector<int> adj[MAXN+10];
pii A[MAXN+10];
int idx[MAXN+10];

vector<int> adj2[MAXN*5+10];
vector<int> radj2[MAXN*5+10];

int dep[MAXN+10], par[MAXN+10], sz[MAXN+10];
void dfs(int now, int bef, int d)
{
	dep[now]=d;
	par[now]=bef;
	sz[now]=1;
	for(int nxt : adj[now])
	{
		if(nxt==bef) continue;
		dfs(nxt, now, d+1);
		sz[now]+=sz[nxt];
	}
}

void addEdge(int u, int v)
{
	//printf("%d %d\n", u, v);
	adj2[u].push_back(v);
	radj2[v].push_back(u);
}

void init(int node, int tl, int tr)
{
	if(tl==tr)
	{
		idx[tl]=node;
		return;
	}
	int mid=tl+tr>>1;
	init(node*2, tl, mid);
	init(node*2+1, mid+1, tr);

	addEdge(M+node*2, M+node);
	addEdge(M+node*2+1, M+node);
	addEdge(M+N+N+node, M+N+N+node*2);
	addEdge(M+N+N+node, M+N+N+node*2+1);
}

void get(int node, int tl, int tr, int l, int r, vector<int> &V)
{
	if(r<tl || tr<l) return;
	if(l<=tl && tr<=r)
	{
		V.push_back(node);
		return;
	}
	int mid=tl+tr>>1;
	get(node*2, tl, mid, l, r, V);
	get(node*2+1, mid+1, tr, l, r, V);
}

int dfn[MAXN+10], head[MAXN+10], dcnt;
void hld(int now, int bef)
{
	dfn[now]=++dcnt;

	int heavy=0;
	for(int nxt : adj[now]) if(nxt!=bef && sz[heavy]<sz[nxt]) heavy=nxt;
	if(!heavy) return;

	head[heavy]=head[now];
	hld(heavy, now);

	for(int nxt : adj[now]) if(nxt!=bef && nxt!=heavy)
	{
		head[nxt]=nxt;
		hld(nxt, now);
	}
}

int vis[MAXN*5+10];
vector<int> S;
void dfs2(int now)
{
	vis[now]=1;
	for(int nxt : adj2[now]) if(!vis[nxt]) dfs2(nxt);
	S.push_back(now);
}

int scc[MAXN+10], scnt;
void dfs3(int now)
{
	scc[now]=scnt;
	for(int nxt : radj2[now]) if(!scc[nxt]) dfs3(nxt);
}

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);
	}

	NN=N*4+M;

	init(1, 1, N);
	dfs(1, 0, 1);

	head[1]=1;
	hld(1, 0);

	for(int i=1; i<=M; i++)
	{
		addEdge(i, idx[dfn[A[i].first]]+M);
		addEdge(idx[dfn[A[i].second]]+M+N+N, i);
	}

	for(int i=1; i<=M; i++)
	{
		int u=A[i].first, v=A[i].second;
		while(head[u]!=head[v])
		{
			if(dep[u]>dep[v]) swap(u, v);

			vector<int> V;
			get(1, 1, N, dfn[head[v]], dfn[v], V);
			for(auto it : V)
			{
				addEdge(it+M, i);
				addEdge(i, it+M+N+N);
			}
			v=par[head[v]];
		}
		if(dep[u]>dep[v]) swap(u, v);
		vector<int> V;
		get(1, 1, N, dfn[u], dfn[v], V);
		for(auto it : V)
		{
			addEdge(it+M, i);
			addEdge(i, it+M+N+N);
		}
	}

	for(int i=1; i<=NN; i++) if(!vis[i]) dfs2(i);
	reverse(S.begin(), S.end());
	for(auto it : S) if(!scc[it]) scnt++, dfs3(it);

	set<int> SS;
	for(int i=1; i<=M; i++) SS.insert(scc[i]);
	return SS.size()==M;
}

void clear()
{
	for(int i=1; i<=N; i++)
	{
		adj[i].clear();
	}
	for(int i=1; i<=NN; i++)
	{
		adj2[i].clear();
		radj2[i].clear();
		vis[i]=0;
		scc[i]=0;
	}
	S.clear();
	dcnt=0;
	scnt=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 'void init(int, int, int)':
jail.cpp:46:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   46 |  int mid=tl+tr>>1;
      |          ~~^~~
jail.cpp: In function 'void get(int, int, int, int, int, std::vector<int>&)':
jail.cpp:64:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   64 |  int mid=tl+tr>>1;
      |          ~~^~~
jail.cpp: In function 'bool solve()':
jail.cpp:166:18: warning: comparison of integer expressions of different signedness: 'std::set<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  166 |  return SS.size()==M;
      |         ~~~~~~~~~^~~
jail.cpp:106:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |  scanf("%d", &N);
      |  ~~~~~^~~~~~~~~~
jail.cpp:110:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  110 |   scanf("%d%d", &u, &v);
      |   ~~~~~^~~~~~~~~~~~~~~~
jail.cpp:114:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  114 |  scanf("%d", &M);
      |  ~~~~~^~~~~~~~~~
jail.cpp:117:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  117 |   scanf("%d%d", &A[i].first, &A[i].second);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
jail.cpp: In function 'int main()':
jail.cpp:189:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  189 |  scanf("%d", &Q);
      |  ~~~~~^~~~~~~~~~

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