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Submission #783526

# Submission time Handle Problem Language Result Execution time Memory
783526 2023-07-15T02:49:55 Z andecaandeci The Xana coup (BOI21_xanadu) C++17
100 / 100
 52 ms 16624 KB 
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define fi first
#define se second

vector<int> adj[100005], depth2[100005];
queue<int> q;
int a[100005], depth1[100005];
bool vis[100005];
ll dp[100005][2][2];

int main() { 
    ios_base::sync_with_stdio(false); cin.tie(NULL);
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j < 2; j++) {
            for (int k = 0; k < 2; k++) dp[i][j][k] = 1e9;
        }
    }
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int i = 1; i <= n; i++) cin >> a[i];
    q.push(1);
    vis[1] = 1;
    while (!q.empty()) {
        int x = q.front();
        q.pop();
        for (auto u : adj[x]) {
            if (vis[u]) continue;
            vis[u] = 1;
            depth1[u] = depth1[x] + 1;
            q.push(u);
        }
    }
    for (int i = 1; i <= n; i++) {
        vis[i] = 0;
        depth2[depth1[i]].push_back(i);
        if ((i != 1) and ((int)adj[i].size() == 1)) dp[i][0][a[i]] = 0, dp[i][1][1 - a[i]] = 1, vis[i] = 1;
    }
    for (int i = n - 1; i >= 0; i--) {
        for (auto x : depth2[i]) {
            if ((x != 1) and ((int)adj[x].size() == 1)) continue;
            dp[x][0][a[x]] = 0, dp[x][1][1 - a[x]] = 1, dp[x][0][1 - a[x]] = 1e9, dp[x][1][a[x]] = 1e9;
            for (auto u : adj[x]) {
                if (!vis[u]) continue;
                ll c1 = dp[x][0][0], c2 = dp[x][0][1], c3 = dp[x][1][0], c4 = dp[x][1][1];
                dp[x][0][0] = min(c1 + dp[u][0][0], c2 + dp[u][1][0]);
                dp[x][0][1] = min(c2 + dp[u][0][0], c1 + dp[u][1][0]);
                dp[x][1][0] = min(c3 + dp[u][0][1], c4 + dp[u][1][1]);
                dp[x][1][1] = min(c4 + dp[u][0][1], c3 + dp[u][1][1]);
            }
            vis[x] = 1;
        }
    }
    ll ans = min(dp[1][0][0], dp[1][1][0]);
    if (ans > n) cout << "impossible\n";
    else cout << ans << "\n";
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 5024 KB Output is correct
2 Correct 2 ms 5036 KB Output is correct
3 Correct 2 ms 4948 KB Output is correct
4 Correct 2 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 5024 KB Output is correct
2 Correct 2 ms 5036 KB Output is correct
3 Correct 2 ms 4948 KB Output is correct
4 Correct 2 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 2 ms 4948 KB Output is correct
7 Correct 2 ms 4948 KB Output is correct
8 Correct 2 ms 4948 KB Output is correct
9 Correct 3 ms 5020 KB Output is correct
10 Correct 2 ms 4948 KB Output is correct
11 Correct 2 ms 5024 KB Output is correct
12 Correct 2 ms 4948 KB Output is correct
13 Correct 2 ms 4948 KB Output is correct
14 Correct 2 ms 4948 KB Output is correct
15 Correct 2 ms 4948 KB Output is correct
16 Correct 2 ms 5024 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 39 ms 16548 KB Output is correct
2 Correct 39 ms 16440 KB Output is correct
3 Correct 39 ms 16532 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 36 ms 16524 KB Output is correct
2 Correct 37 ms 16432 KB Output is correct
3 Correct 40 ms 16624 KB Output is correct
4 Correct 33 ms 13048 KB Output is correct
5 Correct 39 ms 13872 KB Output is correct
6 Correct 36 ms 13968 KB Output is correct
7 Correct 3 ms 5076 KB Output is correct
8 Correct 13 ms 8056 KB Output is correct
9 Correct 39 ms 13864 KB Output is correct
10 Correct 39 ms 13992 KB Output is correct
11 Correct 52 ms 14008 KB Output is correct
12 Correct 49 ms 14332 KB Output is correct
13 Correct 35 ms 13508 KB Output is correct
14 Correct 38 ms 13908 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 5024 KB Output is correct
2 Correct 2 ms 5036 KB Output is correct
3 Correct 2 ms 4948 KB Output is correct
4 Correct 2 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 2 ms 4948 KB Output is correct
7 Correct 2 ms 4948 KB Output is correct
8 Correct 2 ms 4948 KB Output is correct
9 Correct 3 ms 5020 KB Output is correct
10 Correct 2 ms 4948 KB Output is correct
11 Correct 2 ms 5024 KB Output is correct
12 Correct 2 ms 4948 KB Output is correct
13 Correct 2 ms 4948 KB Output is correct
14 Correct 2 ms 4948 KB Output is correct
15 Correct 2 ms 4948 KB Output is correct
16 Correct 2 ms 5024 KB Output is correct
17 Correct 39 ms 16548 KB Output is correct
18 Correct 39 ms 16440 KB Output is correct
19 Correct 39 ms 16532 KB Output is correct
20 Correct 36 ms 16524 KB Output is correct
21 Correct 37 ms 16432 KB Output is correct
22 Correct 40 ms 16624 KB Output is correct
23 Correct 33 ms 13048 KB Output is correct
24 Correct 39 ms 13872 KB Output is correct
25 Correct 36 ms 13968 KB Output is correct
26 Correct 3 ms 5076 KB Output is correct
27 Correct 13 ms 8056 KB Output is correct
28 Correct 39 ms 13864 KB Output is correct
29 Correct 39 ms 13992 KB Output is correct
30 Correct 52 ms 14008 KB Output is correct
31 Correct 49 ms 14332 KB Output is correct
32 Correct 35 ms 13508 KB Output is correct
33 Correct 38 ms 13908 KB Output is correct
34 Correct 2 ms 4948 KB Output is correct
35 Correct 2 ms 5020 KB Output is correct
36 Correct 2 ms 4948 KB Output is correct
37 Correct 2 ms 4948 KB Output is correct
38 Correct 2 ms 5028 KB Output is correct
39 Correct 3 ms 4948 KB Output is correct
40 Correct 2 ms 4948 KB Output is correct
41 Correct 2 ms 4948 KB Output is correct
42 Correct 3 ms 4948 KB Output is correct
43 Correct 3 ms 5028 KB Output is correct
44 Correct 2 ms 5032 KB Output is correct
45 Correct 37 ms 16460 KB Output is correct
46 Correct 36 ms 16384 KB Output is correct
47 Correct 36 ms 16592 KB Output is correct
48 Correct 33 ms 13100 KB Output is correct
49 Correct 38 ms 13780 KB Output is correct
50 Correct 40 ms 13964 KB Output is correct
51 Correct 3 ms 5076 KB Output is correct
52 Correct 14 ms 8044 KB Output is correct
53 Correct 40 ms 13924 KB Output is correct
54 Correct 38 ms 14108 KB Output is correct
55 Correct 39 ms 14012 KB Output is correct
56 Correct 39 ms 14220 KB Output is correct
57 Correct 33 ms 13424 KB Output is correct
58 Correct 40 ms 13968 KB Output is correct
59 Correct 17 ms 8020 KB Output is correct
60 Correct 33 ms 13136 KB Output is correct
61 Correct 38 ms 14048 KB Output is correct
62 Correct 38 ms 14204 KB Output is correct
63 Correct 40 ms 14128 KB Output is correct
64 Correct 38 ms 14180 KB Output is correct
65 Correct 37 ms 14924 KB Output is correct
66 Correct 32 ms 14892 KB Output is correct
67 Correct 33 ms 14852 KB Output is correct
68 Correct 34 ms 14968 KB Output is correct
69 Correct 29 ms 14968 KB Output is correct
70 Correct 30 ms 14932 KB Output is correct