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Submission #672847

# Submission time Handle Problem Language Result Execution time Memory
672847 2022-12-18T12:28:26 Z ParsaS The Xana coup (BOI21_xanadu) C++17
100 / 100
 74 ms 25420 KB 
// In the name of God
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define mp make_pair
typedef long long ll;
const int N = 2e5 + 5;
int n;
vector<int> adj[N];
ll dp[N][2][2];
bool a[N];

void dfs(int v, int p) {
    ll ans[2] = {0, 0}, cnt[2] = {0, 0};
    ll del[2] = {n * 10LL, n * 10LL};
    for (auto u : adj[v]) {
        if (u == p)
            continue;
        dfs(u, v);
        for (int i = 0; i < 2; i++) {
            ans[i] += min(dp[u][0][i], dp[u][1][i]);
            del[i] = min(del[i], (ll)abs(dp[u][0][i] - dp[u][1][i]));
            cnt[i] += dp[u][1][i] <= dp[u][0][i];
        }
    }
    if (adj[v].size() == 1) {
        for (int i = 0; i < 2; i++) {
            dp[v][i][a[v] ^ i] = i;
        }
        return;
    }
    dp[v][0][a[v]] = ans[0] + ((cnt[0] % 2) ? del[0] : 0LL);
    dp[v][0][a[v] ^ 1] = ans[0] + ((cnt[0] % 2) == 0 ? del[0] : 0LL);
    dp[v][1][a[v]] = ans[1] + ((cnt[1] % 2) == 0 ? del[1] : 0LL) + 1;
    dp[v][1][a[v] ^ 1] = ans[1] + ((cnt[1] % 2) ? del[1] : 0LL) + 1;
}

void solve() {
    cin >> n;
    for (int i = 0; i< n - 1; i++) {
        int v, u; cin >> v >> u;
        adj[v].pb(u), adj[u].pb(v);
    }
    int rt = 1;

    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        if (adj[i].size() > 1)
            rt = i;
    }
    for (int i = 0; i <= n; i++)
        for (int j = 0; j < 2; j++)
            for (int k = 0; k < 2; k++)
                dp[i][j][k] = n * 10;
    dfs(rt, 0);
    ll ans = min(dp[rt][0][0], dp[rt][1][0]);
    if (ans <= n)
        cout << ans << endl;
    else
        cout << "impossible" << endl;
}

int32_t main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    solve();
    return 0;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 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 3 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 3 ms 4904 KB Output is correct
7 Correct 2 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4948 KB Output is correct
10 Correct 2 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Correct 3 ms 4948 KB Output is correct
14 Correct 2 ms 4948 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 3 ms 4948 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 50 ms 25284 KB Output is correct
2 Correct 50 ms 25044 KB Output is correct
3 Correct 52 ms 25412 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 74 ms 25232 KB Output is correct
2 Correct 64 ms 25084 KB Output is correct
3 Correct 53 ms 25348 KB Output is correct
4 Correct 43 ms 10580 KB Output is correct
5 Correct 60 ms 11180 KB Output is correct
6 Correct 62 ms 11372 KB Output is correct
7 Correct 2 ms 4948 KB Output is correct
8 Correct 19 ms 7152 KB Output is correct
9 Correct 58 ms 11416 KB Output is correct
10 Correct 49 ms 11472 KB Output is correct
11 Correct 51 ms 12260 KB Output is correct
12 Correct 52 ms 12744 KB Output is correct
13 Correct 46 ms 10964 KB Output is correct
14 Correct 72 ms 11368 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 3 ms 4904 KB Output is correct
7 Correct 2 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4948 KB Output is correct
10 Correct 2 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Correct 3 ms 4948 KB Output is correct
14 Correct 2 ms 4948 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 3 ms 4948 KB Output is correct
17 Correct 50 ms 25284 KB Output is correct
18 Correct 50 ms 25044 KB Output is correct
19 Correct 52 ms 25412 KB Output is correct
20 Correct 74 ms 25232 KB Output is correct
21 Correct 64 ms 25084 KB Output is correct
22 Correct 53 ms 25348 KB Output is correct
23 Correct 43 ms 10580 KB Output is correct
24 Correct 60 ms 11180 KB Output is correct
25 Correct 62 ms 11372 KB Output is correct
26 Correct 2 ms 4948 KB Output is correct
27 Correct 19 ms 7152 KB Output is correct
28 Correct 58 ms 11416 KB Output is correct
29 Correct 49 ms 11472 KB Output is correct
30 Correct 51 ms 12260 KB Output is correct
31 Correct 52 ms 12744 KB Output is correct
32 Correct 46 ms 10964 KB Output is correct
33 Correct 72 ms 11368 KB Output is correct
34 Correct 2 ms 4948 KB Output is correct
35 Correct 4 ms 4948 KB Output is correct
36 Correct 3 ms 4948 KB Output is correct
37 Correct 2 ms 4948 KB Output is correct
38 Correct 4 ms 4948 KB Output is correct
39 Correct 3 ms 4948 KB Output is correct
40 Correct 3 ms 4948 KB Output is correct
41 Correct 2 ms 4948 KB Output is correct
42 Correct 4 ms 4948 KB Output is correct
43 Correct 3 ms 4948 KB Output is correct
44 Correct 3 ms 4948 KB Output is correct
45 Correct 57 ms 25252 KB Output is correct
46 Correct 66 ms 25104 KB Output is correct
47 Correct 69 ms 25420 KB Output is correct
48 Correct 45 ms 10652 KB Output is correct
49 Correct 51 ms 11248 KB Output is correct
50 Correct 53 ms 11340 KB Output is correct
51 Correct 3 ms 4948 KB Output is correct
52 Correct 17 ms 7124 KB Output is correct
53 Correct 58 ms 11328 KB Output is correct
54 Correct 59 ms 11392 KB Output is correct
55 Correct 49 ms 12236 KB Output is correct
56 Correct 56 ms 12756 KB Output is correct
57 Correct 67 ms 10940 KB Output is correct
58 Correct 56 ms 11296 KB Output is correct
59 Correct 16 ms 7104 KB Output is correct
60 Correct 69 ms 10704 KB Output is correct
61 Correct 61 ms 11372 KB Output is correct
62 Correct 50 ms 11412 KB Output is correct
63 Correct 59 ms 11468 KB Output is correct
64 Correct 72 ms 11488 KB Output is correct
65 Correct 45 ms 11852 KB Output is correct
66 Correct 46 ms 11828 KB Output is correct
67 Correct 38 ms 11716 KB Output is correct
68 Correct 39 ms 11696 KB Output is correct
69 Correct 35 ms 11656 KB Output is correct
70 Correct 36 ms 11740 KB Output is correct