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Submission #398477

# Submission time Handle Problem Language Result Execution time Memory
398477 2021-05-04T11:10:13 Z model_code The Xana coup (BOI21_xanadu) C++17
100 / 100
 143 ms 36744 KB 
#include <bits/stdc++.h>

using namespace std;

const int MAXN = 1000000;

int N, L[MAXN], dp[MAXN][2][2];
vector<int> e[MAXN];

void dfs(int i = 0, int p = -1) {
  for (int s = 0; s < 2; s++) {
    dp[i][s][L[i] ^ s] = s;
    dp[i][s][L[i] ^ s ^ 1] = N + 1;
  }
  for (int j : e[i])
    if (j != p) {
      dfs(j, i);
      for (int s = 0; s < 2; s++) {
        int dp0 = dp[i][s][0], dp1 = dp[i][s][1];
        dp[i][s][0] = min(N + 1, min(dp0 + dp[j][0][s], dp1 + dp[j][1][s]));
        dp[i][s][1] = min(N + 1, min(dp0 + dp[j][1][s], dp1 + dp[j][0][s]));
      }
    }
}

int main() {
  cin >> N;
  int A, B;
  for (int i = 0; i < N - 1; i++) {
    cin >> A >> B;
    A--, B--;
    e[A].push_back(B);
    e[B].push_back(A);
  }
  for (int i = 0; i < N; i++)
    cin >> L[i];
  dfs();
  int r = min(dp[0][0][0], dp[0][1][0]);
  if (r > N)
    cout << "impossible\n";
  else
    cout << r << "\n";
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 23756 KB Output is correct
2 Correct 15 ms 23796 KB Output is correct
3 Correct 15 ms 23796 KB Output is correct
4 Correct 15 ms 23728 KB Output is correct
5 Correct 17 ms 23756 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 23756 KB Output is correct
2 Correct 15 ms 23796 KB Output is correct
3 Correct 15 ms 23796 KB Output is correct
4 Correct 15 ms 23728 KB Output is correct
5 Correct 17 ms 23756 KB Output is correct
6 Correct 15 ms 23756 KB Output is correct
7 Correct 14 ms 23800 KB Output is correct
8 Correct 14 ms 23756 KB Output is correct
9 Correct 15 ms 23756 KB Output is correct
10 Correct 15 ms 23772 KB Output is correct
11 Correct 15 ms 23688 KB Output is correct
12 Correct 15 ms 23724 KB Output is correct
13 Correct 15 ms 23720 KB Output is correct
14 Correct 15 ms 23800 KB Output is correct
15 Correct 15 ms 23756 KB Output is correct
16 Correct 15 ms 23756 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 121 ms 36664 KB Output is correct
2 Correct 123 ms 36396 KB Output is correct
3 Correct 124 ms 36744 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 121 ms 36520 KB Output is correct
2 Correct 128 ms 36476 KB Output is correct
3 Correct 128 ms 36676 KB Output is correct
4 Correct 109 ms 28228 KB Output is correct
5 Correct 127 ms 28764 KB Output is correct
6 Correct 124 ms 28868 KB Output is correct
7 Correct 15 ms 23940 KB Output is correct
8 Correct 54 ms 25512 KB Output is correct
9 Correct 130 ms 28816 KB Output is correct
10 Correct 138 ms 29044 KB Output is correct
11 Correct 122 ms 29280 KB Output is correct
12 Correct 134 ms 29472 KB Output is correct
13 Correct 116 ms 28492 KB Output is correct
14 Correct 125 ms 28860 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 23756 KB Output is correct
2 Correct 15 ms 23796 KB Output is correct
3 Correct 15 ms 23796 KB Output is correct
4 Correct 15 ms 23728 KB Output is correct
5 Correct 17 ms 23756 KB Output is correct
6 Correct 15 ms 23756 KB Output is correct
7 Correct 14 ms 23800 KB Output is correct
8 Correct 14 ms 23756 KB Output is correct
9 Correct 15 ms 23756 KB Output is correct
10 Correct 15 ms 23772 KB Output is correct
11 Correct 15 ms 23688 KB Output is correct
12 Correct 15 ms 23724 KB Output is correct
13 Correct 15 ms 23720 KB Output is correct
14 Correct 15 ms 23800 KB Output is correct
15 Correct 15 ms 23756 KB Output is correct
16 Correct 15 ms 23756 KB Output is correct
17 Correct 121 ms 36664 KB Output is correct
18 Correct 123 ms 36396 KB Output is correct
19 Correct 124 ms 36744 KB Output is correct
20 Correct 121 ms 36520 KB Output is correct
21 Correct 128 ms 36476 KB Output is correct
22 Correct 128 ms 36676 KB Output is correct
23 Correct 109 ms 28228 KB Output is correct
24 Correct 127 ms 28764 KB Output is correct
25 Correct 124 ms 28868 KB Output is correct
26 Correct 15 ms 23940 KB Output is correct
27 Correct 54 ms 25512 KB Output is correct
28 Correct 130 ms 28816 KB Output is correct
29 Correct 138 ms 29044 KB Output is correct
30 Correct 122 ms 29280 KB Output is correct
31 Correct 134 ms 29472 KB Output is correct
32 Correct 116 ms 28492 KB Output is correct
33 Correct 125 ms 28860 KB Output is correct
34 Correct 14 ms 23716 KB Output is correct
35 Correct 14 ms 23756 KB Output is correct
36 Correct 14 ms 23672 KB Output is correct
37 Correct 16 ms 23756 KB Output is correct
38 Correct 15 ms 23756 KB Output is correct
39 Correct 14 ms 23692 KB Output is correct
40 Correct 15 ms 23716 KB Output is correct
41 Correct 15 ms 23756 KB Output is correct
42 Correct 15 ms 23756 KB Output is correct
43 Correct 15 ms 23756 KB Output is correct
44 Correct 15 ms 23756 KB Output is correct
45 Correct 124 ms 36620 KB Output is correct
46 Correct 126 ms 36396 KB Output is correct
47 Correct 122 ms 36676 KB Output is correct
48 Correct 114 ms 28332 KB Output is correct
49 Correct 127 ms 28744 KB Output is correct
50 Correct 129 ms 28872 KB Output is correct
51 Correct 16 ms 23808 KB Output is correct
52 Correct 49 ms 25412 KB Output is correct
53 Correct 131 ms 28828 KB Output is correct
54 Correct 126 ms 28924 KB Output is correct
55 Correct 129 ms 29336 KB Output is correct
56 Correct 140 ms 29584 KB Output is correct
57 Correct 117 ms 28484 KB Output is correct
58 Correct 143 ms 28796 KB Output is correct
59 Correct 47 ms 25468 KB Output is correct
60 Correct 114 ms 28356 KB Output is correct
61 Correct 127 ms 28892 KB Output is correct
62 Correct 126 ms 28872 KB Output is correct
63 Correct 125 ms 28904 KB Output is correct
64 Correct 127 ms 28908 KB Output is correct
65 Correct 122 ms 29408 KB Output is correct
66 Correct 119 ms 29344 KB Output is correct
67 Correct 112 ms 29396 KB Output is correct
68 Correct 109 ms 29188 KB Output is correct
69 Correct 108 ms 29256 KB Output is correct
70 Correct 109 ms 29160 KB Output is correct