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Submission #820034

# Submission time Handle Problem Language Result Execution time Memory
820034 2023-08-10T18:14:13 Z MohamedAhmed04 The Xana coup (BOI21_xanadu) C++14
100 / 100
 61 ms 30192 KB 
#include <bits/stdc++.h>

using namespace std ;

const int MAX = 1e5 + 10 ;

int arr[MAX] ;
int n ;

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

int vis[MAX][2] ;
long long dp[MAX][2][2] ;

void dfs(int node , int par , bool toggle)
{
	if(vis[node][toggle])
		return ;
	vis[node][toggle] = 1 ;
	dp[node][toggle][0] = dp[node][toggle][1] = n+1 ;
	int cur = arr[node] ^ toggle ;
	long long sum0 = 0 , sum1 = 1 ;
	vector<long long>v[2] ;
	for(auto &child : adj[node])
	{
		if(child == par)
			continue ;
		dfs(child , node , 0) , dfs(child , node , 1) ;
		sum0 += dp[child][0][0] , sum1 += dp[child][1][0] ;
		v[0].push_back(dp[child][0][1] - dp[child][0][0]) ;
		v[1].push_back(dp[child][1][1] - dp[child][1][0]) ;
	}
	sort(v[0].begin() , v[0].end()) ;
	sort(v[1].begin() , v[1].end()) ;
	if((!cur))
		dp[node][toggle][0] = sum0 ;
	else
		dp[node][toggle][1] = sum1 ;
	for(int i = 0 ; i < v[0].size() ; ++i)
	{
		sum0 += v[0][i] ;
		if((i+1) % 2 == cur)
			dp[node][toggle][0] = min(dp[node][toggle][0] , sum0) ;
	}
	for(int i = 0 ; i < v[1].size() ; ++i)
	{
		sum1 += v[1][i] ;
		if((i+1) % 2 != cur)
			dp[node][toggle][1] = min(dp[node][toggle][1] , sum1) ;
	}
}

int main()
{
	ios_base::sync_with_stdio(0) ;
	cin.tie(0) ;
	cin>>n ;
	for(int i = 0 ; i < n-1 ; ++i)
	{
		int x , y ;
		cin>>x>>y ;
		adj[x].push_back(y) ;
		adj[y].push_back(x) ;
	}
	for(int i = 1 ; i <= n ; ++i)
		cin>>arr[i] ;
	dfs(1 , -1 , 0) ;
	long long ans = min(dp[1][0][0] , dp[1][0][1]) ;
	if(ans > n)
		cout<<"impossible\n" ;
	else
		cout<<ans<<"\n" ;
	return 0 ;
}

Compilation message

xanadu.cpp: In function 'void dfs(int, int, bool)':
xanadu.cpp:39:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |  for(int i = 0 ; i < v[0].size() ; ++i)
      |                  ~~^~~~~~~~~~~~~
xanadu.cpp:45:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |  for(int i = 0 ; i < v[1].size() ; ++i)
      |                  ~~^~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 1 ms 2696 KB Output is correct
4 Correct 2 ms 2704 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 1 ms 2696 KB Output is correct
4 Correct 2 ms 2704 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 1 ms 2644 KB Output is correct
7 Correct 1 ms 2700 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 1 ms 2644 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 2 ms 2700 KB Output is correct
13 Correct 1 ms 2644 KB Output is correct
14 Correct 1 ms 2696 KB Output is correct
15 Correct 1 ms 2644 KB Output is correct
16 Correct 1 ms 2644 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 50 ms 30016 KB Output is correct
2 Correct 52 ms 29704 KB Output is correct
3 Correct 54 ms 30176 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 51 ms 29976 KB Output is correct
2 Correct 52 ms 29748 KB Output is correct
3 Correct 52 ms 30192 KB Output is correct
4 Correct 42 ms 10488 KB Output is correct
5 Correct 45 ms 11176 KB Output is correct
6 Correct 49 ms 11440 KB Output is correct
7 Correct 1 ms 2644 KB Output is correct
8 Correct 16 ms 5716 KB Output is correct
9 Correct 50 ms 11492 KB Output is correct
10 Correct 48 ms 11660 KB Output is correct
11 Correct 50 ms 13048 KB Output is correct
12 Correct 48 ms 13364 KB Output is correct
13 Correct 50 ms 10888 KB Output is correct
14 Correct 46 ms 11360 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 1 ms 2696 KB Output is correct
4 Correct 2 ms 2704 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 1 ms 2644 KB Output is correct
7 Correct 1 ms 2700 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 1 ms 2644 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 2 ms 2700 KB Output is correct
13 Correct 1 ms 2644 KB Output is correct
14 Correct 1 ms 2696 KB Output is correct
15 Correct 1 ms 2644 KB Output is correct
16 Correct 1 ms 2644 KB Output is correct
17 Correct 50 ms 30016 KB Output is correct
18 Correct 52 ms 29704 KB Output is correct
19 Correct 54 ms 30176 KB Output is correct
20 Correct 51 ms 29976 KB Output is correct
21 Correct 52 ms 29748 KB Output is correct
22 Correct 52 ms 30192 KB Output is correct
23 Correct 42 ms 10488 KB Output is correct
24 Correct 45 ms 11176 KB Output is correct
25 Correct 49 ms 11440 KB Output is correct
26 Correct 1 ms 2644 KB Output is correct
27 Correct 16 ms 5716 KB Output is correct
28 Correct 50 ms 11492 KB Output is correct
29 Correct 48 ms 11660 KB Output is correct
30 Correct 50 ms 13048 KB Output is correct
31 Correct 48 ms 13364 KB Output is correct
32 Correct 50 ms 10888 KB Output is correct
33 Correct 46 ms 11360 KB Output is correct
34 Correct 1 ms 2644 KB Output is correct
35 Correct 2 ms 2772 KB Output is correct
36 Correct 1 ms 2644 KB Output is correct
37 Correct 2 ms 2644 KB Output is correct
38 Correct 1 ms 2700 KB Output is correct
39 Correct 1 ms 2700 KB Output is correct
40 Correct 1 ms 2644 KB Output is correct
41 Correct 1 ms 2644 KB Output is correct
42 Correct 2 ms 2660 KB Output is correct
43 Correct 1 ms 2644 KB Output is correct
44 Correct 1 ms 2644 KB Output is correct
45 Correct 53 ms 30100 KB Output is correct
46 Correct 50 ms 29696 KB Output is correct
47 Correct 51 ms 30156 KB Output is correct
48 Correct 42 ms 10424 KB Output is correct
49 Correct 56 ms 11216 KB Output is correct
50 Correct 47 ms 11392 KB Output is correct
51 Correct 2 ms 2644 KB Output is correct
52 Correct 16 ms 5716 KB Output is correct
53 Correct 45 ms 11480 KB Output is correct
54 Correct 48 ms 11672 KB Output is correct
55 Correct 61 ms 13048 KB Output is correct
56 Correct 47 ms 13392 KB Output is correct
57 Correct 45 ms 10816 KB Output is correct
58 Correct 46 ms 11476 KB Output is correct
59 Correct 16 ms 5684 KB Output is correct
60 Correct 42 ms 10584 KB Output is correct
61 Correct 51 ms 11384 KB Output is correct
62 Correct 50 ms 11580 KB Output is correct
63 Correct 48 ms 11648 KB Output is correct
64 Correct 48 ms 11632 KB Output is correct
65 Correct 41 ms 12004 KB Output is correct
66 Correct 45 ms 11940 KB Output is correct
67 Correct 44 ms 14740 KB Output is correct
68 Correct 38 ms 14776 KB Output is correct
69 Correct 39 ms 14752 KB Output is correct
70 Correct 40 ms 14820 KB Output is correct