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Submission #906053

# Submission time Handle Problem Language Result Execution time Memory
906053 2024-01-13T12:21:00 Z Mathias The Xana coup (BOI21_xanadu) C++14
100 / 100
 66 ms 20564 KB 
#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int MAXN = 1e5+7;
const long long INF = 1e9+7;
long long dp[MAXN][3][3];
bool t[MAXN], visited[MAXN];
vector<long long> g[MAXN];
long long n,a,b,c,d;
void DFS(int x,int f){
	visited[x]=1;
	if(t[x]){
		dp[x][1][0]=1;
		dp[x][0][1]=0;
	}
	else{
		dp[x][1][1]=1;
		dp[x][0][0]=0;
	}
	for(int i=0;i<g[x].size();i++){
		if(visited[g[x][i]]==1) continue;
		int s=g[x][i];
		DFS(s,x);
	}
	for(int i=0;i<g[x].size();i++){
		int s=g[x][i];
		if(s==f) continue;
		a=dp[x][0][0], b=dp[x][0][1], c=dp[x][1][0], d=dp[x][1][1];
        dp[x][0][0]=min(a+dp[s][0][0], b+dp[s][1][0]);
        dp[x][0][1]=min(b+dp[s][0][0], a+dp[s][1][0]);
        dp[x][1][0]=min(c+dp[s][0][1], d+dp[s][1][1]);
        dp[x][1][1]=min(d+dp[s][0][1], c+dp[s][1][1]);
	}
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin>>n;
	for(int i=1;i<n;i++){
		cin>>a>>b;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	for(int i=1;i<=n;i++) cin>>t[i];
	for(int i=1;i<=n;i++){
		dp[i][0][0]=INF;
		dp[i][1][0]=INF;
		dp[i][0][1]=INF;
		dp[i][1][1]=INF;
	}
	DFS(1,0);
	if(dp[1][1][0]>n and dp[1][0][0]>n) cout<<"impossible\n";
	else cout<<min(dp[1][1][0], dp[1][0][0])<<'\n';
	return 0;
}

Compilation message

xanadu.cpp: In function 'void DFS(int, int)':
xanadu.cpp:20:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |  for(int i=0;i<g[x].size();i++){
      |              ~^~~~~~~~~~~~
xanadu.cpp:25:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |  for(int i=0;i<g[x].size();i++){
      |              ~^~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 1 ms 4700 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 2 ms 4696 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 1 ms 4700 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 2 ms 4696 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 2 ms 4700 KB Output is correct
7 Correct 1 ms 4700 KB Output is correct
8 Correct 2 ms 4700 KB Output is correct
9 Correct 1 ms 4700 KB Output is correct
10 Correct 1 ms 4700 KB Output is correct
11 Correct 2 ms 4700 KB Output is correct
12 Correct 1 ms 4700 KB Output is correct
13 Correct 2 ms 4696 KB Output is correct
14 Correct 1 ms 4696 KB Output is correct
15 Correct 2 ms 4696 KB Output is correct
16 Correct 1 ms 4700 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 48 ms 19284 KB Output is correct
2 Correct 53 ms 19100 KB Output is correct
3 Correct 38 ms 19284 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 54 ms 19128 KB Output is correct
2 Correct 49 ms 18996 KB Output is correct
3 Correct 39 ms 19284 KB Output is correct
4 Correct 32 ms 12632 KB Output is correct
5 Correct 46 ms 15120 KB Output is correct
6 Correct 58 ms 15384 KB Output is correct
7 Correct 1 ms 4700 KB Output is correct
8 Correct 15 ms 8540 KB Output is correct
9 Correct 40 ms 14680 KB Output is correct
10 Correct 42 ms 14940 KB Output is correct
11 Correct 66 ms 14932 KB Output is correct
12 Correct 38 ms 15296 KB Output is correct
13 Correct 66 ms 14668 KB Output is correct
14 Correct 42 ms 15444 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 1 ms 4700 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 2 ms 4696 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 2 ms 4700 KB Output is correct
7 Correct 1 ms 4700 KB Output is correct
8 Correct 2 ms 4700 KB Output is correct
9 Correct 1 ms 4700 KB Output is correct
10 Correct 1 ms 4700 KB Output is correct
11 Correct 2 ms 4700 KB Output is correct
12 Correct 1 ms 4700 KB Output is correct
13 Correct 2 ms 4696 KB Output is correct
14 Correct 1 ms 4696 KB Output is correct
15 Correct 2 ms 4696 KB Output is correct
16 Correct 1 ms 4700 KB Output is correct
17 Correct 48 ms 19284 KB Output is correct
18 Correct 53 ms 19100 KB Output is correct
19 Correct 38 ms 19284 KB Output is correct
20 Correct 54 ms 19128 KB Output is correct
21 Correct 49 ms 18996 KB Output is correct
22 Correct 39 ms 19284 KB Output is correct
23 Correct 32 ms 12632 KB Output is correct
24 Correct 46 ms 15120 KB Output is correct
25 Correct 58 ms 15384 KB Output is correct
26 Correct 1 ms 4700 KB Output is correct
27 Correct 15 ms 8540 KB Output is correct
28 Correct 40 ms 14680 KB Output is correct
29 Correct 42 ms 14940 KB Output is correct
30 Correct 66 ms 14932 KB Output is correct
31 Correct 38 ms 15296 KB Output is correct
32 Correct 66 ms 14668 KB Output is correct
33 Correct 42 ms 15444 KB Output is correct
34 Correct 1 ms 4700 KB Output is correct
35 Correct 1 ms 4700 KB Output is correct
36 Correct 1 ms 4700 KB Output is correct
37 Correct 2 ms 4696 KB Output is correct
38 Correct 2 ms 4700 KB Output is correct
39 Correct 2 ms 4700 KB Output is correct
40 Correct 1 ms 4700 KB Output is correct
41 Correct 2 ms 4696 KB Output is correct
42 Correct 2 ms 4700 KB Output is correct
43 Correct 2 ms 4748 KB Output is correct
44 Correct 1 ms 4700 KB Output is correct
45 Correct 61 ms 20420 KB Output is correct
46 Correct 56 ms 20376 KB Output is correct
47 Correct 46 ms 20564 KB Output is correct
48 Correct 36 ms 13912 KB Output is correct
49 Correct 45 ms 14936 KB Output is correct
50 Correct 45 ms 15184 KB Output is correct
51 Correct 2 ms 4700 KB Output is correct
52 Correct 12 ms 8396 KB Output is correct
53 Correct 37 ms 14676 KB Output is correct
54 Correct 39 ms 14940 KB Output is correct
55 Correct 48 ms 14928 KB Output is correct
56 Correct 43 ms 15316 KB Output is correct
57 Correct 39 ms 14644 KB Output is correct
58 Correct 41 ms 15692 KB Output is correct
59 Correct 13 ms 8280 KB Output is correct
60 Correct 49 ms 13768 KB Output is correct
61 Correct 38 ms 14740 KB Output is correct
62 Correct 41 ms 14928 KB Output is correct
63 Correct 41 ms 14940 KB Output is correct
64 Correct 43 ms 14932 KB Output is correct
65 Correct 47 ms 15440 KB Output is correct
66 Correct 37 ms 15444 KB Output is correct
67 Correct 32 ms 15308 KB Output is correct
68 Correct 55 ms 15300 KB Output is correct
69 Correct 37 ms 15304 KB Output is correct
70 Correct 36 ms 15304 KB Output is correct