Submission #971499

#	Time	Username	Problem	Language	Result	Execution time	Memory
971499		happy_node	Jail (JOI22_jail)	C++17	49 / 100	5053 ms	252756 KiB

jail

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

const int MX=1.2e5+5;
int Q,N,M;
int S[MX], T[MX];

vector<int> path[MX]; // store the path between Si and Ti

vector<int> adj[MX];

int par[MX];

void dfs(int v, int p) {
	par[v]=p;
	for(auto u:adj[v]) {
		if(u==p) continue;
		dfs(u,v);
	}
}

vector<int> ADJ[MX];
int deg[MX];

bool f(int i, int x) {
	for(auto y:path[i]) 
		if(y==x) return true;
	return false;
}

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

	cin>>Q;

	while(Q--) {
		cin>>N;
		for(int i=1;i<=N;i++) adj[i].clear();

		for(int i=0;i<N-1;i++) {
			int u,v;
			cin>>u>>v;
			adj[u].push_back(v);
			adj[v].push_back(u);
		}

		cin>>M;
		for(int i=0;i<M;i++) path[i].clear(), ADJ[i].clear(), deg[i]=0;

		for(int i=0;i<M;i++) {
			cin>>S[i]>>T[i];
			dfs(S[i],S[i]);

			int p=T[i];
			while(p!=S[i]) {
				path[i].push_back(p);
				p=par[p];
			}
			path[i].push_back(S[i]);
		}

		for(int i=0;i<M;i++) {
			for(int j=i+1;j<M;j++) {
				// check start
				if(f(i,S[j])) {
					ADJ[j].push_back(i);
					deg[i]+=1;
				}
				
				if(f(j,S[i])) {
					ADJ[i].push_back(j);
					deg[j]+=1;
				}

				// check end
				if(f(i,T[j])) {
					ADJ[i].push_back(j);
					deg[j]+=1;
				}

				if(f(j,T[i])) {
					ADJ[j].push_back(i);
					deg[i]+=1;
				}
			}
		}

		queue<int> q;

		for(int i=0;i<M;i++) {
			if(!deg[i]) {
				q.push(i);
			}
		}

		int ans=0;
		while(!q.empty()) {
			auto v=q.front(); q.pop();
			ans+=1;
			for(auto u:ADJ[v]) {
				deg[u]--;
				if(!deg[u]) q.push(u);
			}
		}

		cout<<(ans==M?"Yes":"No")<<'\n';
	}


}

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