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Submission #715329

# Submission time Handle Problem Language Result Execution time Memory
715329 2023-03-26T13:25:23 Z stevancv The Xana coup (BOI21_xanadu) C++14
100 / 100
 86 ms 16920 KB 
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 1e5 + 2;
const int inf = 1e9;
int dp[N][2][2], a[N];
vector<int> g[N];
void Dfs(int s, int e) {
    for (int j = 0; j < 4; j++) dp[s][j / 2][j % 2] = inf;
    if (g[s].size() == 1 && g[s][0] == e) {
        dp[s][a[s]][0] = 0;
        dp[s][1 - a[s]][1] = 1;
        return;
    }
    for (int u : g[s]) if (u != e) Dfs(u, s);
    int cnt, sum, mn, moze;
    cnt = sum = 0;
    mn = inf;
    moze = 1;
    for (int u : g[s]) {
        if (u == e) continue;
        sum += min(dp[u][0][0], dp[u][0][1]);
        if (min(dp[u][0][0], dp[u][0][1]) == inf) moze = 0;
        smin(mn, abs(dp[u][0][0] - dp[u][0][1]));
        if (dp[u][0][0] > dp[u][0][1]) cnt += 1;
    }
    if (moze == 1) {
        dp[s][0][0] = sum;
        if (mn <= 1000000) dp[s][1][0] = sum + mn;
        if ((cnt + a[s]) % 2 == 1) swap(dp[s][0][0], dp[s][1][0]);
    }
    cnt = sum = 0;
    mn = inf;
    moze = 1;
    for (int u : g[s]) {
        if (u == e) continue;
        sum += min(dp[u][1][0], dp[u][1][1]);
        if (min(dp[u][1][0], dp[u][1][1]) == inf) moze = 0;
        smin(mn, abs(dp[u][1][0] - dp[u][1][1]));
        if (dp[u][1][0] > dp[u][1][1]) cnt += 1;
    }
    if (moze == 1) {
        dp[s][0][1] = sum + 1;
        if (mn <= 1000000) dp[s][1][1] = sum + mn + 1;
        if ((cnt + a[s]) % 2 == 0) swap(dp[s][0][1], dp[s][1][1]);
    }
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n; cin >> n;
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    for (int i = 1; i <= n; i++) cin >> a[i];
    Dfs(1, 0);
    int ans = min(dp[1][0][0], dp[1][0][1]);
    if (ans == inf) cout << "impossible" << en;
    else cout << ans << en;
    return 0;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 1 ms 2644 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 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 2 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 2644 KB Output is correct
9 Correct 1 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 2644 KB Output is correct
15 Correct 2 ms 2676 KB Output is correct
16 Correct 2 ms 2680 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 61 ms 16752 KB Output is correct
2 Correct 48 ms 16588 KB Output is correct
3 Correct 57 ms 16816 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 57 ms 16816 KB Output is correct
2 Correct 64 ms 16596 KB Output is correct
3 Correct 71 ms 16800 KB Output is correct
4 Correct 51 ms 8360 KB Output is correct
5 Correct 48 ms 8860 KB Output is correct
6 Correct 52 ms 9052 KB Output is correct
7 Correct 2 ms 2644 KB Output is correct
8 Correct 18 ms 4844 KB Output is correct
9 Correct 65 ms 9068 KB Output is correct
10 Correct 86 ms 9080 KB Output is correct
11 Correct 77 ms 9528 KB Output is correct
12 Correct 61 ms 9736 KB Output is correct
13 Correct 48 ms 8616 KB Output is correct
14 Correct 45 ms 9096 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 1 ms 2644 KB Output is correct
5 Correct 2 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 2644 KB Output is correct
9 Correct 1 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 2644 KB Output is correct
15 Correct 2 ms 2676 KB Output is correct
16 Correct 2 ms 2680 KB Output is correct
17 Correct 61 ms 16752 KB Output is correct
18 Correct 48 ms 16588 KB Output is correct
19 Correct 57 ms 16816 KB Output is correct
20 Correct 57 ms 16816 KB Output is correct
21 Correct 64 ms 16596 KB Output is correct
22 Correct 71 ms 16800 KB Output is correct
23 Correct 51 ms 8360 KB Output is correct
24 Correct 48 ms 8860 KB Output is correct
25 Correct 52 ms 9052 KB Output is correct
26 Correct 2 ms 2644 KB Output is correct
27 Correct 18 ms 4844 KB Output is correct
28 Correct 65 ms 9068 KB Output is correct
29 Correct 86 ms 9080 KB Output is correct
30 Correct 77 ms 9528 KB Output is correct
31 Correct 61 ms 9736 KB Output is correct
32 Correct 48 ms 8616 KB Output is correct
33 Correct 45 ms 9096 KB Output is correct
34 Correct 1 ms 2644 KB Output is correct
35 Correct 2 ms 2644 KB Output is correct
36 Correct 2 ms 2644 KB Output is correct
37 Correct 2 ms 2644 KB Output is correct
38 Correct 2 ms 2684 KB Output is correct
39 Correct 2 ms 2644 KB Output is correct
40 Correct 2 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 63 ms 16756 KB Output is correct
46 Correct 55 ms 16580 KB Output is correct
47 Correct 59 ms 16920 KB Output is correct
48 Correct 52 ms 8396 KB Output is correct
49 Correct 64 ms 8964 KB Output is correct
50 Correct 53 ms 9076 KB Output is correct
51 Correct 2 ms 2644 KB Output is correct
52 Correct 16 ms 4732 KB Output is correct
53 Correct 51 ms 9072 KB Output is correct
54 Correct 68 ms 9096 KB Output is correct
55 Correct 65 ms 9516 KB Output is correct
56 Correct 53 ms 9816 KB Output is correct
57 Correct 45 ms 8572 KB Output is correct
58 Correct 49 ms 9092 KB Output is correct
59 Correct 22 ms 4708 KB Output is correct
60 Correct 51 ms 8432 KB Output is correct
61 Correct 54 ms 9036 KB Output is correct
62 Correct 60 ms 9240 KB Output is correct
63 Correct 47 ms 9184 KB Output is correct
64 Correct 53 ms 9120 KB Output is correct
65 Correct 39 ms 9636 KB Output is correct
66 Correct 39 ms 9636 KB Output is correct
67 Correct 39 ms 9504 KB Output is correct
68 Correct 40 ms 9396 KB Output is correct
69 Correct 36 ms 9472 KB Output is correct
70 Correct 34 ms 9420 KB Output is correct