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Submission #748078

# Submission time Handle Problem Language Result Execution time Memory
748078 2023-05-25T11:35:25 Z vjudge1 From Hacks to Snitches (BOI21_watchmen) C++17
0 / 100
 6000 ms 17820 KB 
#include<bits/stdc++.h>
using namespace std;
const int maxn=250000+10;
vector<int>adj[maxn],allk[maxn];
int n,m,k,nowk[maxn],dp[2][maxn],now=1,vis[maxn],nexta[maxn];

int bad(int i){
	int ret=nowk[i]+1;
	ret%=(int)allk[i].size();
	return ret;
}

void upd(int ind){
	now^=1;
	for(int i=1;i<=n;i++){
		if(vis[i]==ind){
			dp[now][i]=0;
			continue;
		}
		if(dp[now^1][i]==1)
		{
			dp[now][i]=1;
			continue;
		}
		int f=0;
		for(auto x:adj[i]){
			if(dp[now^1][x]==1){
				if(vis[i]!=ind-1){
					f=1;
					break;
				}	
				if(nexta[i]!=x){
					f=1;
					break;
				}
			}
		}
		if(f){
			dp[now][i]=1;
		}
		else{
			dp[now][i]=0;
		}
	}
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>m;
	for(int i=0;i<m;i++){
		int u,v;
		cin>>u>>v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	cin>>k;
	for(int i=1;i<=k;i++){
		int ki;
		cin>>ki;
		allk[i].resize(ki);
		for(int j=0;j<ki;j++){
			cin>>allk[i][j];
		}
	}
	for(int i=0;i<=n;i++){
		vis[i]=-1;
	}
	for(int i=1;i<=k;i++){
		vis[allk[i][0]]=0;
	}
	dp[1][1]=1;
	int res=-1;
	for(int i=1;i<=k+n+2;i++){
		for(int j=1;j<=k;j++){
			nexta[allk[j][nowk[j]]]=allk[j][bad(j)];
			nowk[j]=bad(j);
			vis[allk[j][nowk[j]]]=i;
		//	cout<<nowk[j]<<" "<<allk[j][nowk[j]]<<"\n";
		}
		upd(i);
	//	for(int j=1;j<=n;j++){
	///		cout<<i<<" "<<j<<" "<<dp[now][j]<<"\n";
	//	}
		if(dp[now][n]==1){
			res=i;
			break;
		}
	}
	if(res==-1){
		cout<<"impossible\n";
	}
	else{
		cout<<res<<"\n";
	}
}

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 13524 KB Output is correct
2 Execution timed out 6053 ms 17800 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 13524 KB Output is correct
2 Execution timed out 6049 ms 17820 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 13524 KB Output is correct
2 Execution timed out 6049 ms 17820 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 13524 KB Output is correct
2 Execution timed out 6049 ms 17820 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #5
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 13524 KB Output is correct
2 Execution timed out 6053 ms 17800 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 13524 KB Output is correct
2 Execution timed out 6053 ms 17800 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 13524 KB Output is correct
2 Execution timed out 6053 ms 17800 KB Time limit exceeded
3 Halted 0 ms 0 KB -