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Submission #643965

# Submission time Handle Problem Language Result Execution time Memory
643965 2022-09-23T10:29:02 Z alextodoran The Xana coup (BOI21_xanadu) C++17
100 / 100
 74 ms 18180 KB 
/**
 ____ ____ ____ ____ ____
||a |||t |||o |||d |||o ||
||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|

**/

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int N_MAX = 100000;
const int INF = INT_MAX / 2;

int N;
vector <int> adj[N_MAX + 2];
bool on[N_MAX + 2];

int dp[N_MAX + 2][2][2];

void dfs (int u, int parent = 0) {
    int sum[2][2];
    sum[0][0] = sum[0][1] = 0;
    sum[1][0] = sum[1][1] = INF;
    for (int v : adj[u]) {
        if (v != parent) {
            dfs(v, u);
            int old[2][2];
            old[0][0] = sum[0][0]; old[0][1] = sum[0][1];
            old[1][0] = sum[1][0]; old[1][1] = sum[1][1];
            sum[0][0] = min({old[0][0] + dp[v][0][0], old[1][0] + dp[v][1][0], INF});
            sum[0][1] = min({old[0][1] + dp[v][0][1], old[1][1] + dp[v][1][1], INF});
            sum[1][0] = min({old[0][0] + dp[v][1][0], old[1][0] + dp[v][0][0], INF});
            sum[1][1] = min({old[0][1] + dp[v][1][1], old[1][1] + dp[v][0][1], INF});
        }
    }
    if (on[u] == 1) {
        dp[u][0][0] = sum[1][0];
        dp[u][0][1] = sum[0][0];
        dp[u][1][0] = sum[0][1] + 1;
        dp[u][1][1] = sum[1][1] + 1;
    } else {
        dp[u][0][0] = sum[0][0];
        dp[u][0][1] = sum[1][0];
        dp[u][1][0] = sum[1][1] + 1;
        dp[u][1][1] = sum[0][1] + 1;
    }
}

int main () {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    cin >> N;
    for (int i = 1; i <= N - 1; i++) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int u = 1; u <= N; u++) {
        cin >> on[u];
    }
    dfs(1);
    int answer = min(dp[1][0][0], dp[1][1][0]);
    if (answer <= N) {
        cout << answer << "\n";
    } else {
        cout << "impossible\n";
    }

    return 0;
}

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 2680 KB Output is correct
4 Correct 2 ms 2676 KB Output is correct
5 Correct 1 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 2680 KB Output is correct
4 Correct 2 ms 2676 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 2 ms 2644 KB Output is correct
8 Correct 2 ms 2676 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 2 ms 2644 KB Output is correct
13 Correct 2 ms 2644 KB Output is correct
14 Correct 2 ms 2664 KB Output is correct
15 Correct 1 ms 2676 KB Output is correct
16 Correct 2 ms 2672 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 49 ms 18124 KB Output is correct
2 Correct 61 ms 17816 KB Output is correct
3 Correct 57 ms 18180 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 52 ms 18072 KB Output is correct
2 Correct 46 ms 17904 KB Output is correct
3 Correct 46 ms 18124 KB Output is correct
4 Correct 38 ms 8124 KB Output is correct
5 Correct 48 ms 8656 KB Output is correct
6 Correct 60 ms 8792 KB Output is correct
7 Correct 2 ms 2644 KB Output is correct
8 Correct 17 ms 4664 KB Output is correct
9 Correct 67 ms 8676 KB Output is correct
10 Correct 49 ms 8788 KB Output is correct
11 Correct 49 ms 9432 KB Output is correct
12 Correct 50 ms 9608 KB Output is correct
13 Correct 52 ms 8308 KB Output is correct
14 Correct 66 ms 8700 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 2680 KB Output is correct
4 Correct 2 ms 2676 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 2 ms 2644 KB Output is correct
8 Correct 2 ms 2676 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 2 ms 2644 KB Output is correct
13 Correct 2 ms 2644 KB Output is correct
14 Correct 2 ms 2664 KB Output is correct
15 Correct 1 ms 2676 KB Output is correct
16 Correct 2 ms 2672 KB Output is correct
17 Correct 49 ms 18124 KB Output is correct
18 Correct 61 ms 17816 KB Output is correct
19 Correct 57 ms 18180 KB Output is correct
20 Correct 52 ms 18072 KB Output is correct
21 Correct 46 ms 17904 KB Output is correct
22 Correct 46 ms 18124 KB Output is correct
23 Correct 38 ms 8124 KB Output is correct
24 Correct 48 ms 8656 KB Output is correct
25 Correct 60 ms 8792 KB Output is correct
26 Correct 2 ms 2644 KB Output is correct
27 Correct 17 ms 4664 KB Output is correct
28 Correct 67 ms 8676 KB Output is correct
29 Correct 49 ms 8788 KB Output is correct
30 Correct 49 ms 9432 KB Output is correct
31 Correct 50 ms 9608 KB Output is correct
32 Correct 52 ms 8308 KB Output is correct
33 Correct 66 ms 8700 KB Output is correct
34 Correct 2 ms 2680 KB Output is correct
35 Correct 2 ms 2644 KB Output is correct
36 Correct 2 ms 2644 KB Output is correct
37 Correct 1 ms 2644 KB Output is correct
38 Correct 2 ms 2676 KB Output is correct
39 Correct 1 ms 2644 KB Output is correct
40 Correct 1 ms 2644 KB Output is correct
41 Correct 2 ms 2644 KB Output is correct
42 Correct 2 ms 2644 KB Output is correct
43 Correct 2 ms 2644 KB Output is correct
44 Correct 2 ms 2644 KB Output is correct
45 Correct 74 ms 17996 KB Output is correct
46 Correct 48 ms 17876 KB Output is correct
47 Correct 48 ms 18120 KB Output is correct
48 Correct 40 ms 8060 KB Output is correct
49 Correct 53 ms 8652 KB Output is correct
50 Correct 58 ms 8708 KB Output is correct
51 Correct 2 ms 2644 KB Output is correct
52 Correct 20 ms 4672 KB Output is correct
53 Correct 64 ms 8712 KB Output is correct
54 Correct 46 ms 8780 KB Output is correct
55 Correct 46 ms 9348 KB Output is correct
56 Correct 50 ms 9644 KB Output is correct
57 Correct 49 ms 8288 KB Output is correct
58 Correct 63 ms 8784 KB Output is correct
59 Correct 20 ms 4672 KB Output is correct
60 Correct 39 ms 8104 KB Output is correct
61 Correct 45 ms 8704 KB Output is correct
62 Correct 63 ms 8784 KB Output is correct
63 Correct 72 ms 8860 KB Output is correct
64 Correct 49 ms 8840 KB Output is correct
65 Correct 41 ms 9364 KB Output is correct
66 Correct 43 ms 9280 KB Output is correct
67 Correct 37 ms 9196 KB Output is correct
68 Correct 36 ms 9176 KB Output is correct
69 Correct 35 ms 9120 KB Output is correct
70 Correct 48 ms 9152 KB Output is correct