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Submission #409884

# Submission time Handle Problem Language Result Execution time Memory
409884 2021-05-21T17:58:09 Z CaroLinda The Xana coup (BOI21_xanadu) C++14
100 / 100
 101 ms 15328 KB 
#include <bits/stdc++.h>

#define ll long long
#define all(x) x.begin(),x.end()

const int MAXN = 1e5+10 ;

using namespace std ;

int N ;
int color[MAXN] ;
int dp[MAXN][2][2] ; //color, should click
vector<int> adj[MAXN] ;

void dfs(int x, int par )
{
	bool is_leaf = true ;

	for(auto e : adj[x])
	{
		if(e == par ) continue ;
		
		dfs(e,x) ;
		is_leaf = false ;
	}

	if(is_leaf)
	{

		dp[x][0][0] = 0 ;
		dp[x][0][1] = N+5 ;
		dp[x][1][0] = N+5 ;
		dp[x][1][1] = 1 ;

		return ;
	}

	int ans = 0 ;
	int min_coin = 2*N+10 ;
	int qtd = 0 ;

	//should not click
	for(auto e : adj[x] )
	{
		if(e == par ) continue ;

		if( dp[e][ color[e] ][0] <= dp[e][ color[e] ][1] )
		{
			ans += dp[e][ color[e] ][0] ;
			min_coin = min(min_coin , dp[e][ color[e] ][1] - dp[e][ color[e] ][0] ) ;
		}
		else
		{
			ans += dp[e][ color[e] ][1] ;
			min_coin = min( min_coin , dp[e][ color[e] ][0] - dp[e][ color[e] ][1] ) ;
			qtd ^= 1 ;
		}
	}

	if(qtd)
	{
		dp[x][1][0] = ans ;
		dp[x][0][0] = ans+min_coin ;
	}
	else
	{
		dp[x][1][0] = ans+min_coin ;
		dp[x][0][0] = ans ;
	}

	//should click
	ans = 1 ;
	min_coin = 2*N+10 ;
	qtd = 0 ;

	for(auto e : adj[x] ) 
	{
		if(e == par ) continue ;

		int mx = max( dp[e][!color[e]][0] , dp[e][!color[e]][1] ) ;
		int mn = min( dp[e][!color[e]][0] , dp[e][!color[e]][1] ) ;

		ans += mn ;
		min_coin = min(min_coin , mx-mn ) ;

		if( dp[e][!color[e]][0] > dp[e][ !color[e] ][1] ) qtd ^= 1 ;

	}

	if( qtd )
	{
		dp[x][0][1] = ans ;
		dp[x][1][1] = ans+min_coin ;
	}
	else
	{
		dp[x][0][1] = ans+min_coin ;
		dp[x][1][1] = ans; 
	}

	for(int i = 0 ; i < 2 ; i++ )
		for(int j = 0 ; j< 2 ; j++ )
			dp[x][i][j] = min(dp[x][i][j] , N+5) ;

	/*cout << x << endl ;
	for(int i = 0 ; i < 2 ; i++ , cout << endl )
		for(int j = 0 ; j < 2 ; j++ ) cout << dp[x][i][j] <<" " ;
	cout << endl ;*/

}

int main()
{
	scanf("%d", &N ) ;
	for(int i = 1 , u ,v ; i < N ; i++ )
	{
		scanf("%d %d", &u, &v ) ;
		adj[u].push_back(v) ;
		adj[v].push_back(u) ;
	}
	for(int i = 1 ; i <= N ; i++ ) scanf("%d", &color[i] ) ;

	dfs(1,-1) ;

	int ans = min( dp[1][color[1]][0] , dp[1][color[1]][1] ) ;

	if(ans == N+5 ) printf("impossible\n") ;
	else printf("%d\n" , ans ) ;
}

Compilation message

xanadu.cpp: In function 'int main()':
xanadu.cpp:114:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  114 |  scanf("%d", &N ) ;
      |  ~~~~~^~~~~~~~~~~
xanadu.cpp:117:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  117 |   scanf("%d %d", &u, &v ) ;
      |   ~~~~~^~~~~~~~~~~~~~~~~~
xanadu.cpp:121:38: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  121 |  for(int i = 1 ; i <= N ; i++ ) scanf("%d", &color[i] ) ;
      |                                 ~~~~~^~~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2656 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2652 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2656 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2652 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 2 ms 2652 KB Output is correct
7 Correct 3 ms 2636 KB Output is correct
8 Correct 2 ms 2636 KB Output is correct
9 Correct 2 ms 2656 KB Output is correct
10 Correct 2 ms 2636 KB Output is correct
11 Correct 2 ms 2636 KB Output is correct
12 Correct 2 ms 2636 KB Output is correct
13 Correct 2 ms 2656 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 2 ms 2660 KB Output is correct
16 Correct 2 ms 2656 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 68 ms 15224 KB Output is correct
2 Correct 67 ms 15044 KB Output is correct
3 Correct 73 ms 15224 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 82 ms 15180 KB Output is correct
2 Correct 75 ms 15044 KB Output is correct
3 Correct 78 ms 15328 KB Output is correct
4 Correct 63 ms 8384 KB Output is correct
5 Correct 76 ms 8880 KB Output is correct
6 Correct 71 ms 8972 KB Output is correct
7 Correct 2 ms 2636 KB Output is correct
8 Correct 21 ms 4768 KB Output is correct
9 Correct 82 ms 9008 KB Output is correct
10 Correct 77 ms 9136 KB Output is correct
11 Correct 75 ms 9412 KB Output is correct
12 Correct 78 ms 9576 KB Output is correct
13 Correct 68 ms 8656 KB Output is correct
14 Correct 75 ms 8972 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2656 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2652 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct
6 Correct 2 ms 2652 KB Output is correct
7 Correct 3 ms 2636 KB Output is correct
8 Correct 2 ms 2636 KB Output is correct
9 Correct 2 ms 2656 KB Output is correct
10 Correct 2 ms 2636 KB Output is correct
11 Correct 2 ms 2636 KB Output is correct
12 Correct 2 ms 2636 KB Output is correct
13 Correct 2 ms 2656 KB Output is correct
14 Correct 2 ms 2636 KB Output is correct
15 Correct 2 ms 2660 KB Output is correct
16 Correct 2 ms 2656 KB Output is correct
17 Correct 68 ms 15224 KB Output is correct
18 Correct 67 ms 15044 KB Output is correct
19 Correct 73 ms 15224 KB Output is correct
20 Correct 82 ms 15180 KB Output is correct
21 Correct 75 ms 15044 KB Output is correct
22 Correct 78 ms 15328 KB Output is correct
23 Correct 63 ms 8384 KB Output is correct
24 Correct 76 ms 8880 KB Output is correct
25 Correct 71 ms 8972 KB Output is correct
26 Correct 2 ms 2636 KB Output is correct
27 Correct 21 ms 4768 KB Output is correct
28 Correct 82 ms 9008 KB Output is correct
29 Correct 77 ms 9136 KB Output is correct
30 Correct 75 ms 9412 KB Output is correct
31 Correct 78 ms 9576 KB Output is correct
32 Correct 68 ms 8656 KB Output is correct
33 Correct 75 ms 8972 KB Output is correct
34 Correct 2 ms 2636 KB Output is correct
35 Correct 2 ms 2652 KB Output is correct
36 Correct 3 ms 2636 KB Output is correct
37 Correct 2 ms 2572 KB Output is correct
38 Correct 2 ms 2636 KB Output is correct
39 Correct 2 ms 2636 KB Output is correct
40 Correct 2 ms 2636 KB Output is correct
41 Correct 2 ms 2636 KB Output is correct
42 Correct 2 ms 2636 KB Output is correct
43 Correct 2 ms 2636 KB Output is correct
44 Correct 2 ms 2636 KB Output is correct
45 Correct 90 ms 15220 KB Output is correct
46 Correct 76 ms 15092 KB Output is correct
47 Correct 66 ms 15300 KB Output is correct
48 Correct 60 ms 8332 KB Output is correct
49 Correct 73 ms 8824 KB Output is correct
50 Correct 101 ms 9012 KB Output is correct
51 Correct 3 ms 2636 KB Output is correct
52 Correct 21 ms 4684 KB Output is correct
53 Correct 72 ms 8992 KB Output is correct
54 Correct 78 ms 9028 KB Output is correct
55 Correct 71 ms 9344 KB Output is correct
56 Correct 77 ms 9560 KB Output is correct
57 Correct 76 ms 8616 KB Output is correct
58 Correct 97 ms 8964 KB Output is correct
59 Correct 21 ms 4676 KB Output is correct
60 Correct 69 ms 8328 KB Output is correct
61 Correct 68 ms 8884 KB Output is correct
62 Correct 86 ms 9060 KB Output is correct
63 Correct 73 ms 9192 KB Output is correct
64 Correct 73 ms 9132 KB Output is correct
65 Correct 62 ms 9592 KB Output is correct
66 Correct 61 ms 9492 KB Output is correct
67 Correct 57 ms 9404 KB Output is correct
68 Correct 57 ms 9404 KB Output is correct
69 Correct 61 ms 9452 KB Output is correct
70 Correct 76 ms 9468 KB Output is correct