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Submission #817663

# Submission time Handle Problem Language Result Execution time Memory
817663 2023-08-09T14:49:38 Z MohamedAhmed04 From Hacks to Snitches (BOI21_watchmen) C++14
35 / 100
 6000 ms 193812 KB 
#include <bits/stdc++.h>

using namespace std ;

const int inf = 1e9 ;
const int MAX = 3e5 + 10 ;
const int K = 130 ;

int arr[MAX] ;
int n , m , k ;

vector< vector<int> >adj(MAX) ;

vector<int>v[MAX] ;
int watch[MAX] , cycle_sz[MAX] , id[MAX] ;

int dist[MAX][K] ;

bool check(int node , int child , int tim)
{
	assert(watch[child] != 0) ;
	int x = watch[node] ;
	int tim_node = 2e9 ;
	if(watch[node])
	{
		int cur = tim % cycle_sz[x] ;
		tim_node = tim + (id[node] - cur + cycle_sz[x]) % cycle_sz[x] ;
	}
	int tim_child = -2e9 ;
	x = watch[child] ;
	int cur = tim % cycle_sz[x] ;
	tim_child = tim + (id[child] - cur + cycle_sz[x]) % cycle_sz[x] ;
	return (tim_child < tim_node-1 || (tim_child == tim_node - 1 && watch[child] != watch[node])) ;
}

void solve(int src)
{
	for(int i = 1 ; i <= n ; ++i)
		dist[i][0] = dist[i][1] = inf ;
	priority_queue< array<int , 3> , vector< array<int , 3> > , greater< array<int , 3> > >q ;
	dist[src][0] = 0 ;
	q.push({0 , src , 0}) ;
	while(!q.empty())
	{
		array<int , 3>a = q.top() ;
		q.pop() ;
		int node = a[1] , cost = a[0] , t = a[2] ;
		if(dist[node][t] < cost)
			continue ;
		for(auto &child : adj[node])
		{
			int child2 = child ;
			int cost2 = cost + 1 ;
			if((!watch[child2]))
			{
				if(cost2 < dist[child2][0])
				{
					dist[child2][0] = cost2 ;
					q.push({cost2 , child2 , 0}) ;
				}
				continue ;
			}
			int x = watch[child2] ;
			if(check(node , child2 , cost)) //handle waiting for some time
			{
				int cur = cost % cycle_sz[x] ;
				cost2 = cost + (id[child2] - cur + cycle_sz[x]) % cycle_sz[x] + 1 ; 
				if(cost2 < dist[child2][1])
				{
					dist[child2][1] = cost2 ;
					q.push({cost2 , child2 , 1}) ;
				}
			}
			cost2 = cost + 1 ;
			//handle corridor 
			if(v[x][(cost2 - 1) % cycle_sz[x]] == child2 && v[x][cost2 % cycle_sz[x]] == node)
				continue ;
			if(v[x][cost2 % cycle_sz[x]] != child2) //go without waiting
			{
				if(cost2 < dist[child2][t])
				{
					dist[child2][t] = cost2 ;
					q.push({cost2 , child2 , t}) ;
				}
			}
		}
	}
}

void solve2(int src)
{
	for(int i = 1 ; i <= n ; ++i)
	{
		for(int j = 0 ; j < K ; ++j)
			dist[i][j] = inf ;
	}
	queue< pair<int , int> >q ;
	dist[src][0] = 0 ;
	q.push({src , 0}) ;
	while(!q.empty())
	{
		pair<int , int>p = q.front() ;
		q.pop() ;
		int node = p.first , wait = p.second ;
		int cost = dist[node][wait] , x = watch[node] ;
		if((!x) || (v[x][(cost + 1) % cycle_sz[x]] != node))
		{
			if(wait+1 < K && dist[node][wait+1] == inf)
			{
				dist[node][wait+1] = cost + 1 ;
				q.push({node , wait+1}) ;
			}
		}
		for(auto &child : adj[node])
		{
			int child2 = child ;
			int cost2 = cost + 1 ;
			x = watch[child] ;
			if(x > 0 && v[x][(cost2 - 1) % cycle_sz[x]] == child2 && v[x][cost2 % cycle_sz[x]] == node)
				continue ;
			if(x > 0 && v[x][cost2 % cycle_sz[x]] == child2)
				continue ;
			if(dist[child2][wait] == inf)
			{
				dist[child2][wait] = cost2 ;
				q.push({child2 , wait}) ;
			}
		}
	}
}

int main()
{
	ios_base::sync_with_stdio(0) ;
	cin.tie(0) ;
	cin>>n>>m ;
	for(int i = 0 ; i < m ; ++i)
	{
		int x , y ;
		cin>>x>>y ;
		adj[x].push_back(y) ;
		adj[y].push_back(x) ;
	}
	cin>>k ;
	for(int i = 1 ; i <= k ; ++i)
	{
		cin>>cycle_sz[i] ;
		v[i].resize(cycle_sz[i]) ;
		for(int j = 0 ; j < cycle_sz[i] ; ++j)
		{
			cin>>v[i][j] ;
			watch[v[i][j]] = i ;
			id[v[i][j]] = j ;
		}
	}
	bool flag = true ;
	for(int i = 1 ; i <= n ; ++i)
	{
		for(auto &child : adj[i])
			flag &= (watch[i] == 0 || watch[child] == 0 || watch[i] == watch[child]) ;
	}
	if(flag) //no corridor connects two two different routes
	{
		solve(1) ;
		if(dist[n][0] == inf)
			cout<<"impossible\n" ;
		else
			cout<<dist[n][0]<<"\n" ;
	}
	else
	{
		solve2(1) ;
		int ans = inf ;
		for(int i = 0 ; i < K ; ++i)
			ans = min(ans , dist[n][i]) ;
		if(ans == inf)
			cout<<"impossible\n" ;
		else
			cout<<ans<<"\n" ;
	}
	return 0 ;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15572 KB Output is correct
2 Correct 70 ms 68896 KB Output is correct
3 Correct 69 ms 63692 KB Output is correct
4 Correct 76 ms 63872 KB Output is correct
5 Correct 7 ms 14420 KB Output is correct
6 Correct 81 ms 63712 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 15512 KB Output is correct
2 Correct 74 ms 68872 KB Output is correct
3 Correct 70 ms 63764 KB Output is correct
4 Correct 70 ms 63820 KB Output is correct
5 Correct 8 ms 14460 KB Output is correct
6 Correct 76 ms 63708 KB Output is correct
7 Correct 68 ms 63732 KB Output is correct
8 Correct 81 ms 63712 KB Output is correct
9 Correct 69 ms 63676 KB Output is correct
10 Correct 65 ms 63880 KB Output is correct
11 Correct 83 ms 63760 KB Output is correct
12 Correct 73 ms 63652 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 15512 KB Output is correct
2 Correct 74 ms 68872 KB Output is correct
3 Correct 70 ms 63764 KB Output is correct
4 Correct 70 ms 63820 KB Output is correct
5 Correct 8 ms 14460 KB Output is correct
6 Correct 76 ms 63708 KB Output is correct
7 Correct 68 ms 63732 KB Output is correct
8 Correct 81 ms 63712 KB Output is correct
9 Correct 69 ms 63676 KB Output is correct
10 Correct 65 ms 63880 KB Output is correct
11 Correct 83 ms 63760 KB Output is correct
12 Correct 73 ms 63652 KB Output is correct
13 Correct 18 ms 15568 KB Output is correct
14 Correct 94 ms 68908 KB Output is correct
15 Correct 68 ms 63724 KB Output is correct
16 Correct 72 ms 63788 KB Output is correct
17 Correct 7 ms 14420 KB Output is correct
18 Correct 77 ms 63752 KB Output is correct
19 Correct 72 ms 63724 KB Output is correct
20 Correct 66 ms 63664 KB Output is correct
21 Correct 72 ms 63640 KB Output is correct
22 Correct 66 ms 63876 KB Output is correct
23 Correct 75 ms 63812 KB Output is correct
24 Correct 83 ms 63656 KB Output is correct
25 Correct 1307 ms 186556 KB Output is correct
26 Correct 1020 ms 192876 KB Output is correct
27 Correct 1048 ms 186216 KB Output is correct
28 Correct 840 ms 191184 KB Output is correct
29 Correct 1146 ms 180332 KB Output is correct
30 Correct 1329 ms 183704 KB Output is correct
31 Correct 1469 ms 193312 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 15512 KB Output is correct
2 Correct 74 ms 68872 KB Output is correct
3 Correct 70 ms 63764 KB Output is correct
4 Correct 70 ms 63820 KB Output is correct
5 Correct 8 ms 14460 KB Output is correct
6 Correct 76 ms 63708 KB Output is correct
7 Correct 68 ms 63732 KB Output is correct
8 Correct 81 ms 63712 KB Output is correct
9 Correct 69 ms 63676 KB Output is correct
10 Correct 65 ms 63880 KB Output is correct
11 Correct 83 ms 63760 KB Output is correct
12 Correct 73 ms 63652 KB Output is correct
13 Correct 18 ms 15568 KB Output is correct
14 Correct 94 ms 68908 KB Output is correct
15 Correct 68 ms 63724 KB Output is correct
16 Correct 72 ms 63788 KB Output is correct
17 Correct 7 ms 14420 KB Output is correct
18 Correct 77 ms 63752 KB Output is correct
19 Correct 72 ms 63724 KB Output is correct
20 Correct 66 ms 63664 KB Output is correct
21 Correct 72 ms 63640 KB Output is correct
22 Correct 66 ms 63876 KB Output is correct
23 Correct 75 ms 63812 KB Output is correct
24 Correct 83 ms 63656 KB Output is correct
25 Correct 1307 ms 186556 KB Output is correct
26 Correct 1020 ms 192876 KB Output is correct
27 Correct 1048 ms 186216 KB Output is correct
28 Correct 840 ms 191184 KB Output is correct
29 Correct 1146 ms 180332 KB Output is correct
30 Correct 1329 ms 183704 KB Output is correct
31 Correct 1469 ms 193312 KB Output is correct
32 Correct 17 ms 15508 KB Output is correct
33 Correct 67 ms 68912 KB Output is correct
34 Correct 74 ms 63668 KB Output is correct
35 Correct 81 ms 63840 KB Output is correct
36 Correct 7 ms 14420 KB Output is correct
37 Correct 86 ms 63752 KB Output is correct
38 Correct 78 ms 63712 KB Output is correct
39 Correct 80 ms 63752 KB Output is correct
40 Correct 85 ms 63672 KB Output is correct
41 Correct 84 ms 63880 KB Output is correct
42 Correct 74 ms 63816 KB Output is correct
43 Correct 83 ms 63748 KB Output is correct
44 Correct 1464 ms 186604 KB Output is correct
45 Correct 1173 ms 192884 KB Output is correct
46 Correct 948 ms 186256 KB Output is correct
47 Correct 812 ms 191064 KB Output is correct
48 Correct 1069 ms 180232 KB Output is correct
49 Correct 1135 ms 183672 KB Output is correct
50 Correct 1111 ms 193328 KB Output is correct
51 Correct 1074 ms 187348 KB Output is correct
52 Correct 906 ms 193812 KB Output is correct
53 Correct 893 ms 185996 KB Output is correct
54 Correct 812 ms 179752 KB Output is correct
55 Correct 1222 ms 185952 KB Output is correct
56 Correct 1236 ms 179724 KB Output is correct

Subtask #5
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15572 KB Output is correct
2 Correct 70 ms 68896 KB Output is correct
3 Correct 69 ms 63692 KB Output is correct
4 Correct 76 ms 63872 KB Output is correct
5 Correct 7 ms 14420 KB Output is correct
6 Correct 81 ms 63712 KB Output is correct
7 Correct 21 ms 15512 KB Output is correct
8 Correct 74 ms 68872 KB Output is correct
9 Correct 70 ms 63764 KB Output is correct
10 Correct 70 ms 63820 KB Output is correct
11 Correct 8 ms 14460 KB Output is correct
12 Correct 76 ms 63708 KB Output is correct
13 Correct 68 ms 63732 KB Output is correct
14 Correct 81 ms 63712 KB Output is correct
15 Correct 69 ms 63676 KB Output is correct
16 Correct 65 ms 63880 KB Output is correct
17 Correct 83 ms 63760 KB Output is correct
18 Correct 73 ms 63652 KB Output is correct
19 Correct 7 ms 14420 KB Output is correct
20 Correct 7 ms 14420 KB Output is correct
21 Correct 7 ms 14388 KB Output is correct
22 Correct 17 ms 15504 KB Output is correct
23 Correct 70 ms 68880 KB Output is correct
24 Correct 69 ms 63724 KB Output is correct
25 Correct 87 ms 63868 KB Output is correct
26 Correct 7 ms 14420 KB Output is correct
27 Correct 78 ms 63744 KB Output is correct
28 Correct 70 ms 63748 KB Output is correct
29 Correct 76 ms 63836 KB Output is correct
30 Correct 67 ms 63692 KB Output is correct
31 Correct 65 ms 63876 KB Output is correct
32 Correct 71 ms 63780 KB Output is correct
33 Correct 68 ms 63724 KB Output is correct
34 Execution timed out 6064 ms 187792 KB Time limit exceeded
35 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15572 KB Output is correct
2 Correct 70 ms 68896 KB Output is correct
3 Correct 69 ms 63692 KB Output is correct
4 Correct 76 ms 63872 KB Output is correct
5 Correct 7 ms 14420 KB Output is correct
6 Correct 81 ms 63712 KB Output is correct
7 Correct 21 ms 15512 KB Output is correct
8 Correct 74 ms 68872 KB Output is correct
9 Correct 70 ms 63764 KB Output is correct
10 Correct 70 ms 63820 KB Output is correct
11 Correct 8 ms 14460 KB Output is correct
12 Correct 76 ms 63708 KB Output is correct
13 Correct 68 ms 63732 KB Output is correct
14 Correct 81 ms 63712 KB Output is correct
15 Correct 69 ms 63676 KB Output is correct
16 Correct 65 ms 63880 KB Output is correct
17 Correct 83 ms 63760 KB Output is correct
18 Correct 73 ms 63652 KB Output is correct
19 Correct 18 ms 15568 KB Output is correct
20 Correct 94 ms 68908 KB Output is correct
21 Correct 68 ms 63724 KB Output is correct
22 Correct 72 ms 63788 KB Output is correct
23 Correct 7 ms 14420 KB Output is correct
24 Correct 77 ms 63752 KB Output is correct
25 Correct 72 ms 63724 KB Output is correct
26 Correct 66 ms 63664 KB Output is correct
27 Correct 72 ms 63640 KB Output is correct
28 Correct 66 ms 63876 KB Output is correct
29 Correct 75 ms 63812 KB Output is correct
30 Correct 83 ms 63656 KB Output is correct
31 Correct 1307 ms 186556 KB Output is correct
32 Correct 1020 ms 192876 KB Output is correct
33 Correct 1048 ms 186216 KB Output is correct
34 Correct 840 ms 191184 KB Output is correct
35 Correct 1146 ms 180332 KB Output is correct
36 Correct 1329 ms 183704 KB Output is correct
37 Correct 1469 ms 193312 KB Output is correct
38 Correct 7 ms 14420 KB Output is correct
39 Correct 7 ms 14420 KB Output is correct
40 Correct 7 ms 14388 KB Output is correct
41 Correct 17 ms 15504 KB Output is correct
42 Correct 70 ms 68880 KB Output is correct
43 Correct 69 ms 63724 KB Output is correct
44 Correct 87 ms 63868 KB Output is correct
45 Correct 7 ms 14420 KB Output is correct
46 Correct 78 ms 63744 KB Output is correct
47 Correct 70 ms 63748 KB Output is correct
48 Correct 76 ms 63836 KB Output is correct
49 Correct 67 ms 63692 KB Output is correct
50 Correct 65 ms 63876 KB Output is correct
51 Correct 71 ms 63780 KB Output is correct
52 Correct 68 ms 63724 KB Output is correct
53 Execution timed out 6064 ms 187792 KB Time limit exceeded
54 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15572 KB Output is correct
2 Correct 70 ms 68896 KB Output is correct
3 Correct 69 ms 63692 KB Output is correct
4 Correct 76 ms 63872 KB Output is correct
5 Correct 7 ms 14420 KB Output is correct
6 Correct 81 ms 63712 KB Output is correct
7 Correct 21 ms 15512 KB Output is correct
8 Correct 74 ms 68872 KB Output is correct
9 Correct 70 ms 63764 KB Output is correct
10 Correct 70 ms 63820 KB Output is correct
11 Correct 8 ms 14460 KB Output is correct
12 Correct 76 ms 63708 KB Output is correct
13 Correct 68 ms 63732 KB Output is correct
14 Correct 81 ms 63712 KB Output is correct
15 Correct 69 ms 63676 KB Output is correct
16 Correct 65 ms 63880 KB Output is correct
17 Correct 83 ms 63760 KB Output is correct
18 Correct 73 ms 63652 KB Output is correct
19 Correct 18 ms 15568 KB Output is correct
20 Correct 94 ms 68908 KB Output is correct
21 Correct 68 ms 63724 KB Output is correct
22 Correct 72 ms 63788 KB Output is correct
23 Correct 7 ms 14420 KB Output is correct
24 Correct 77 ms 63752 KB Output is correct
25 Correct 72 ms 63724 KB Output is correct
26 Correct 66 ms 63664 KB Output is correct
27 Correct 72 ms 63640 KB Output is correct
28 Correct 66 ms 63876 KB Output is correct
29 Correct 75 ms 63812 KB Output is correct
30 Correct 83 ms 63656 KB Output is correct
31 Correct 1307 ms 186556 KB Output is correct
32 Correct 1020 ms 192876 KB Output is correct
33 Correct 1048 ms 186216 KB Output is correct
34 Correct 840 ms 191184 KB Output is correct
35 Correct 1146 ms 180332 KB Output is correct
36 Correct 1329 ms 183704 KB Output is correct
37 Correct 1469 ms 193312 KB Output is correct
38 Correct 17 ms 15508 KB Output is correct
39 Correct 67 ms 68912 KB Output is correct
40 Correct 74 ms 63668 KB Output is correct
41 Correct 81 ms 63840 KB Output is correct
42 Correct 7 ms 14420 KB Output is correct
43 Correct 86 ms 63752 KB Output is correct
44 Correct 78 ms 63712 KB Output is correct
45 Correct 80 ms 63752 KB Output is correct
46 Correct 85 ms 63672 KB Output is correct
47 Correct 84 ms 63880 KB Output is correct
48 Correct 74 ms 63816 KB Output is correct
49 Correct 83 ms 63748 KB Output is correct
50 Correct 1464 ms 186604 KB Output is correct
51 Correct 1173 ms 192884 KB Output is correct
52 Correct 948 ms 186256 KB Output is correct
53 Correct 812 ms 191064 KB Output is correct
54 Correct 1069 ms 180232 KB Output is correct
55 Correct 1135 ms 183672 KB Output is correct
56 Correct 1111 ms 193328 KB Output is correct
57 Correct 1074 ms 187348 KB Output is correct
58 Correct 906 ms 193812 KB Output is correct
59 Correct 893 ms 185996 KB Output is correct
60 Correct 812 ms 179752 KB Output is correct
61 Correct 1222 ms 185952 KB Output is correct
62 Correct 1236 ms 179724 KB Output is correct
63 Correct 7 ms 14420 KB Output is correct
64 Correct 7 ms 14420 KB Output is correct
65 Correct 7 ms 14388 KB Output is correct
66 Correct 17 ms 15504 KB Output is correct
67 Correct 70 ms 68880 KB Output is correct
68 Correct 69 ms 63724 KB Output is correct
69 Correct 87 ms 63868 KB Output is correct
70 Correct 7 ms 14420 KB Output is correct
71 Correct 78 ms 63744 KB Output is correct
72 Correct 70 ms 63748 KB Output is correct
73 Correct 76 ms 63836 KB Output is correct
74 Correct 67 ms 63692 KB Output is correct
75 Correct 65 ms 63876 KB Output is correct
76 Correct 71 ms 63780 KB Output is correct
77 Correct 68 ms 63724 KB Output is correct
78 Execution timed out 6064 ms 187792 KB Time limit exceeded
79 Halted 0 ms 0 KB -