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Submission #817685

# Submission time Handle Problem Language Result Execution time Memory
817685 2023-08-09T15:01:28 Z MohamedAhmed04 From Hacks to Snitches (BOI21_watchmen) C++14
35 / 100
 6000 ms 161636 KB 
#include <bits/stdc++.h>

using namespace std ;

const int inf = 1e9 ;
const int MAX = 3e5 + 10 ;
const int K = 50 ;

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] ;

int calc[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(node == n)
			return ;
		if((!x) || (v[x][calc[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][calc[cost2 - 1][cycle_sz[x]]] == child2 && v[x][calc[cost2][cycle_sz[x]]] == node)
				continue ;
			if(x > 0 && v[x][calc[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
	{
		for(int j = 1 ; j < K ; ++j)
		{
			calc[0][j] = 0 ;
			for(int i = 1 ; i < n + 1000 ; ++i)
			{
				calc[i][j] = calc[i-1][j] + 1 ;
				if(calc[i][j] == j)
					calc[i][j] = 0 ;
			}
		}
		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 15456 KB Output is correct
2 Correct 59 ms 37588 KB Output is correct
3 Correct 62 ms 35604 KB Output is correct
4 Correct 60 ms 35716 KB Output is correct
5 Correct 8 ms 14352 KB Output is correct
6 Correct 74 ms 35504 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15536 KB Output is correct
2 Correct 67 ms 37588 KB Output is correct
3 Correct 61 ms 35552 KB Output is correct
4 Correct 74 ms 35724 KB Output is correct
5 Correct 7 ms 14420 KB Output is correct
6 Correct 61 ms 35536 KB Output is correct
7 Correct 68 ms 35588 KB Output is correct
8 Correct 56 ms 35560 KB Output is correct
9 Correct 63 ms 35520 KB Output is correct
10 Correct 55 ms 35660 KB Output is correct
11 Correct 62 ms 35564 KB Output is correct
12 Correct 62 ms 35544 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15536 KB Output is correct
2 Correct 67 ms 37588 KB Output is correct
3 Correct 61 ms 35552 KB Output is correct
4 Correct 74 ms 35724 KB Output is correct
5 Correct 7 ms 14420 KB Output is correct
6 Correct 61 ms 35536 KB Output is correct
7 Correct 68 ms 35588 KB Output is correct
8 Correct 56 ms 35560 KB Output is correct
9 Correct 63 ms 35520 KB Output is correct
10 Correct 55 ms 35660 KB Output is correct
11 Correct 62 ms 35564 KB Output is correct
12 Correct 62 ms 35544 KB Output is correct
13 Correct 18 ms 15460 KB Output is correct
14 Correct 67 ms 37572 KB Output is correct
15 Correct 64 ms 35512 KB Output is correct
16 Correct 79 ms 35660 KB Output is correct
17 Correct 7 ms 14420 KB Output is correct
18 Correct 64 ms 35576 KB Output is correct
19 Correct 56 ms 35564 KB Output is correct
20 Correct 76 ms 35564 KB Output is correct
21 Correct 56 ms 35504 KB Output is correct
22 Correct 72 ms 35720 KB Output is correct
23 Correct 59 ms 35508 KB Output is correct
24 Correct 61 ms 35496 KB Output is correct
25 Correct 1149 ms 108396 KB Output is correct
26 Correct 972 ms 114632 KB Output is correct
27 Correct 902 ms 108004 KB Output is correct
28 Correct 854 ms 112888 KB Output is correct
29 Correct 1133 ms 101912 KB Output is correct
30 Correct 1154 ms 105372 KB Output is correct
31 Correct 1267 ms 115060 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15536 KB Output is correct
2 Correct 67 ms 37588 KB Output is correct
3 Correct 61 ms 35552 KB Output is correct
4 Correct 74 ms 35724 KB Output is correct
5 Correct 7 ms 14420 KB Output is correct
6 Correct 61 ms 35536 KB Output is correct
7 Correct 68 ms 35588 KB Output is correct
8 Correct 56 ms 35560 KB Output is correct
9 Correct 63 ms 35520 KB Output is correct
10 Correct 55 ms 35660 KB Output is correct
11 Correct 62 ms 35564 KB Output is correct
12 Correct 62 ms 35544 KB Output is correct
13 Correct 18 ms 15460 KB Output is correct
14 Correct 67 ms 37572 KB Output is correct
15 Correct 64 ms 35512 KB Output is correct
16 Correct 79 ms 35660 KB Output is correct
17 Correct 7 ms 14420 KB Output is correct
18 Correct 64 ms 35576 KB Output is correct
19 Correct 56 ms 35564 KB Output is correct
20 Correct 76 ms 35564 KB Output is correct
21 Correct 56 ms 35504 KB Output is correct
22 Correct 72 ms 35720 KB Output is correct
23 Correct 59 ms 35508 KB Output is correct
24 Correct 61 ms 35496 KB Output is correct
25 Correct 1149 ms 108396 KB Output is correct
26 Correct 972 ms 114632 KB Output is correct
27 Correct 902 ms 108004 KB Output is correct
28 Correct 854 ms 112888 KB Output is correct
29 Correct 1133 ms 101912 KB Output is correct
30 Correct 1154 ms 105372 KB Output is correct
31 Correct 1267 ms 115060 KB Output is correct
32 Correct 22 ms 15444 KB Output is correct
33 Correct 65 ms 37584 KB Output is correct
34 Correct 66 ms 35660 KB Output is correct
35 Correct 64 ms 35724 KB Output is correct
36 Correct 7 ms 14420 KB Output is correct
37 Correct 61 ms 35568 KB Output is correct
38 Correct 64 ms 35588 KB Output is correct
39 Correct 77 ms 35556 KB Output is correct
40 Correct 72 ms 35496 KB Output is correct
41 Correct 72 ms 35724 KB Output is correct
42 Correct 62 ms 35528 KB Output is correct
43 Correct 63 ms 35588 KB Output is correct
44 Correct 1179 ms 108192 KB Output is correct
45 Correct 1046 ms 114548 KB Output is correct
46 Correct 999 ms 108036 KB Output is correct
47 Correct 831 ms 112832 KB Output is correct
48 Correct 1134 ms 101840 KB Output is correct
49 Correct 1101 ms 105416 KB Output is correct
50 Correct 1212 ms 115092 KB Output is correct
51 Correct 1184 ms 109028 KB Output is correct
52 Correct 1018 ms 115524 KB Output is correct
53 Correct 957 ms 107832 KB Output is correct
54 Correct 764 ms 101576 KB Output is correct
55 Correct 1271 ms 107772 KB Output is correct
56 Correct 1250 ms 101564 KB Output is correct

Subtask #5
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15456 KB Output is correct
2 Correct 59 ms 37588 KB Output is correct
3 Correct 62 ms 35604 KB Output is correct
4 Correct 60 ms 35716 KB Output is correct
5 Correct 8 ms 14352 KB Output is correct
6 Correct 74 ms 35504 KB Output is correct
7 Correct 19 ms 15536 KB Output is correct
8 Correct 67 ms 37588 KB Output is correct
9 Correct 61 ms 35552 KB Output is correct
10 Correct 74 ms 35724 KB Output is correct
11 Correct 7 ms 14420 KB Output is correct
12 Correct 61 ms 35536 KB Output is correct
13 Correct 68 ms 35588 KB Output is correct
14 Correct 56 ms 35560 KB Output is correct
15 Correct 63 ms 35520 KB Output is correct
16 Correct 55 ms 35660 KB Output is correct
17 Correct 62 ms 35564 KB Output is correct
18 Correct 62 ms 35544 KB Output is correct
19 Correct 7 ms 14420 KB Output is correct
20 Correct 8 ms 14492 KB Output is correct
21 Correct 8 ms 14548 KB Output is correct
22 Correct 17 ms 15372 KB Output is correct
23 Correct 59 ms 37568 KB Output is correct
24 Correct 61 ms 35564 KB Output is correct
25 Correct 60 ms 35612 KB Output is correct
26 Correct 7 ms 14420 KB Output is correct
27 Correct 62 ms 35528 KB Output is correct
28 Correct 74 ms 35488 KB Output is correct
29 Correct 67 ms 35552 KB Output is correct
30 Correct 60 ms 35584 KB Output is correct
31 Correct 58 ms 35712 KB Output is correct
32 Correct 57 ms 35568 KB Output is correct
33 Correct 61 ms 35548 KB Output is correct
34 Correct 5868 ms 158644 KB Output is correct
35 Correct 5809 ms 161636 KB Output is correct
36 Execution timed out 6067 ms 161388 KB Time limit exceeded
37 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15456 KB Output is correct
2 Correct 59 ms 37588 KB Output is correct
3 Correct 62 ms 35604 KB Output is correct
4 Correct 60 ms 35716 KB Output is correct
5 Correct 8 ms 14352 KB Output is correct
6 Correct 74 ms 35504 KB Output is correct
7 Correct 19 ms 15536 KB Output is correct
8 Correct 67 ms 37588 KB Output is correct
9 Correct 61 ms 35552 KB Output is correct
10 Correct 74 ms 35724 KB Output is correct
11 Correct 7 ms 14420 KB Output is correct
12 Correct 61 ms 35536 KB Output is correct
13 Correct 68 ms 35588 KB Output is correct
14 Correct 56 ms 35560 KB Output is correct
15 Correct 63 ms 35520 KB Output is correct
16 Correct 55 ms 35660 KB Output is correct
17 Correct 62 ms 35564 KB Output is correct
18 Correct 62 ms 35544 KB Output is correct
19 Correct 18 ms 15460 KB Output is correct
20 Correct 67 ms 37572 KB Output is correct
21 Correct 64 ms 35512 KB Output is correct
22 Correct 79 ms 35660 KB Output is correct
23 Correct 7 ms 14420 KB Output is correct
24 Correct 64 ms 35576 KB Output is correct
25 Correct 56 ms 35564 KB Output is correct
26 Correct 76 ms 35564 KB Output is correct
27 Correct 56 ms 35504 KB Output is correct
28 Correct 72 ms 35720 KB Output is correct
29 Correct 59 ms 35508 KB Output is correct
30 Correct 61 ms 35496 KB Output is correct
31 Correct 1149 ms 108396 KB Output is correct
32 Correct 972 ms 114632 KB Output is correct
33 Correct 902 ms 108004 KB Output is correct
34 Correct 854 ms 112888 KB Output is correct
35 Correct 1133 ms 101912 KB Output is correct
36 Correct 1154 ms 105372 KB Output is correct
37 Correct 1267 ms 115060 KB Output is correct
38 Correct 7 ms 14420 KB Output is correct
39 Correct 8 ms 14492 KB Output is correct
40 Correct 8 ms 14548 KB Output is correct
41 Correct 17 ms 15372 KB Output is correct
42 Correct 59 ms 37568 KB Output is correct
43 Correct 61 ms 35564 KB Output is correct
44 Correct 60 ms 35612 KB Output is correct
45 Correct 7 ms 14420 KB Output is correct
46 Correct 62 ms 35528 KB Output is correct
47 Correct 74 ms 35488 KB Output is correct
48 Correct 67 ms 35552 KB Output is correct
49 Correct 60 ms 35584 KB Output is correct
50 Correct 58 ms 35712 KB Output is correct
51 Correct 57 ms 35568 KB Output is correct
52 Correct 61 ms 35548 KB Output is correct
53 Correct 5868 ms 158644 KB Output is correct
54 Correct 5809 ms 161636 KB Output is correct
55 Execution timed out 6067 ms 161388 KB Time limit exceeded
56 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 15456 KB Output is correct
2 Correct 59 ms 37588 KB Output is correct
3 Correct 62 ms 35604 KB Output is correct
4 Correct 60 ms 35716 KB Output is correct
5 Correct 8 ms 14352 KB Output is correct
6 Correct 74 ms 35504 KB Output is correct
7 Correct 19 ms 15536 KB Output is correct
8 Correct 67 ms 37588 KB Output is correct
9 Correct 61 ms 35552 KB Output is correct
10 Correct 74 ms 35724 KB Output is correct
11 Correct 7 ms 14420 KB Output is correct
12 Correct 61 ms 35536 KB Output is correct
13 Correct 68 ms 35588 KB Output is correct
14 Correct 56 ms 35560 KB Output is correct
15 Correct 63 ms 35520 KB Output is correct
16 Correct 55 ms 35660 KB Output is correct
17 Correct 62 ms 35564 KB Output is correct
18 Correct 62 ms 35544 KB Output is correct
19 Correct 18 ms 15460 KB Output is correct
20 Correct 67 ms 37572 KB Output is correct
21 Correct 64 ms 35512 KB Output is correct
22 Correct 79 ms 35660 KB Output is correct
23 Correct 7 ms 14420 KB Output is correct
24 Correct 64 ms 35576 KB Output is correct
25 Correct 56 ms 35564 KB Output is correct
26 Correct 76 ms 35564 KB Output is correct
27 Correct 56 ms 35504 KB Output is correct
28 Correct 72 ms 35720 KB Output is correct
29 Correct 59 ms 35508 KB Output is correct
30 Correct 61 ms 35496 KB Output is correct
31 Correct 1149 ms 108396 KB Output is correct
32 Correct 972 ms 114632 KB Output is correct
33 Correct 902 ms 108004 KB Output is correct
34 Correct 854 ms 112888 KB Output is correct
35 Correct 1133 ms 101912 KB Output is correct
36 Correct 1154 ms 105372 KB Output is correct
37 Correct 1267 ms 115060 KB Output is correct
38 Correct 22 ms 15444 KB Output is correct
39 Correct 65 ms 37584 KB Output is correct
40 Correct 66 ms 35660 KB Output is correct
41 Correct 64 ms 35724 KB Output is correct
42 Correct 7 ms 14420 KB Output is correct
43 Correct 61 ms 35568 KB Output is correct
44 Correct 64 ms 35588 KB Output is correct
45 Correct 77 ms 35556 KB Output is correct
46 Correct 72 ms 35496 KB Output is correct
47 Correct 72 ms 35724 KB Output is correct
48 Correct 62 ms 35528 KB Output is correct
49 Correct 63 ms 35588 KB Output is correct
50 Correct 1179 ms 108192 KB Output is correct
51 Correct 1046 ms 114548 KB Output is correct
52 Correct 999 ms 108036 KB Output is correct
53 Correct 831 ms 112832 KB Output is correct
54 Correct 1134 ms 101840 KB Output is correct
55 Correct 1101 ms 105416 KB Output is correct
56 Correct 1212 ms 115092 KB Output is correct
57 Correct 1184 ms 109028 KB Output is correct
58 Correct 1018 ms 115524 KB Output is correct
59 Correct 957 ms 107832 KB Output is correct
60 Correct 764 ms 101576 KB Output is correct
61 Correct 1271 ms 107772 KB Output is correct
62 Correct 1250 ms 101564 KB Output is correct
63 Correct 7 ms 14420 KB Output is correct
64 Correct 8 ms 14492 KB Output is correct
65 Correct 8 ms 14548 KB Output is correct
66 Correct 17 ms 15372 KB Output is correct
67 Correct 59 ms 37568 KB Output is correct
68 Correct 61 ms 35564 KB Output is correct
69 Correct 60 ms 35612 KB Output is correct
70 Correct 7 ms 14420 KB Output is correct
71 Correct 62 ms 35528 KB Output is correct
72 Correct 74 ms 35488 KB Output is correct
73 Correct 67 ms 35552 KB Output is correct
74 Correct 60 ms 35584 KB Output is correct
75 Correct 58 ms 35712 KB Output is correct
76 Correct 57 ms 35568 KB Output is correct
77 Correct 61 ms 35548 KB Output is correct
78 Correct 5868 ms 158644 KB Output is correct
79 Correct 5809 ms 161636 KB Output is correct
80 Execution timed out 6067 ms 161388 KB Time limit exceeded
81 Halted 0 ms 0 KB -