Submission #1017623

#	Time	Username	Problem	Language	Result	Execution time	Memory
1017623		Unforgettablepl	Jail (JOI22_jail)	C++17	0 / 100	14 ms	860 KiB

jail

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

#define int long long

const int modulo = 1e9+7;

void solve(){
	int n;
	cin >> n;
	vector<vector<int>> adj(n+1);
	for(int i=1;i<n;i++){
		int a,b;cin>>a>>b;
		adj[a].emplace_back(b);
		adj[b].emplace_back(a);
	}
	vector<int> depth(n+1);
	vector<vector<int>> p(n+1,vector<int>(17));
	function<void(int,int,int)> dfs = [&](int x,int par,int dep){
		depth[x]=dep;
		p[x][0]=par;
		for(int&i:adj[x])if(i!=par)dfs(i,x,dep+1);
	};
	dfs(1,0,1);
	for(int bit=1;bit<17;bit++){
		for(int i=1;i<=n;i++){
			p[i][bit] = p[p[i][bit-1]][bit-1];
		}
	}
	auto lift = [&](int x,int tar){
		for(int bit=0;bit<17;bit++)if(tar&(1<<bit))x=p[x][bit];
		return x;
	};
	int m;
	cin >> m;
	vector<vector<int>> secadj(m+1);
	vector<int> s(m+1);
	vector<int> t(m+1);
	auto collides = [&](int curr,int v){
		int a = s[curr];
		int b = t[curr];
		if(a==v or b==v)return true;
		bool worksa = false;
		if(depth[a]>=depth[v] and lift(a,depth[a]-depth[v])==v)worksa=true;
		bool worksb = false;
		if(depth[b]>=depth[v] and lift(b,depth[b]-depth[v])==v)worksb=true;
		if(worksa and worksb){
			return lift(a,depth[a]-depth[v]-1)!=lift(b,depth[b]-depth[v]-1);
		} else return worksa or worksb;
	};
	for(int i=1;i<=m;i++){
		cin >> s[i] >> t[i];
		for(int j=1;j<i;j++){
			if(collides(i,t[j]))secadj[j].emplace_back(i);
			if(collides(i,s[j]))secadj[i].emplace_back(j);
		}
	}
	vector<int> visited(m+1);
	bool works = true;
	function<void(int)> secdfs = [&](int x){
		if(visited[x]==2)return;
		if(visited[x]==1){
			works = false;
			return;
		}
		visited[x]=1;
		for(int&i:secadj[x])secdfs(i);
		visited[x]=2;
	};
	for(int i=1;i<=m;i++)secdfs(i);
	if(works){
		cout << "Yes\n";
	} else cout << "No\n";
}

int32_t main(){
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	int t;
	cin >> t;
	while(t--)solve();
}

• 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