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Submission #869554

# Submission time Handle Problem Language Result Execution time Memory
869554 2023-11-04T17:35:10 Z wakandaaa The Xana coup (BOI21_xanadu) C++17
100 / 100
 56 ms 42920 KB 
#include <bits/stdc++.h>

using namespace std;

#define file ""

#define mp make_pair
#define fi first
#define se second
#define all(x) x.begin(), x.end()

#define getbit(x, i) (((x) >> (i)) & 1)
#define bit(x) (1LL << (x))
#define popcount __builtin_popcountll

mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r) {
    return l + rd() % (r - l + 1);
}

const int N = 1e6 + 5;
const int mod = (int)1e9 + 7; // 998244353;
const int lg = 25; // lg + 1
const int oo = 1e9;
const long long ooo = 1e18;

template<class X, class Y> bool mini(X &a, Y b) {
    return a > b ? (a = b, true) : false;
}
template<class X, class Y> bool maxi(X &a, Y b) {
    return a < b ? (a = b, true) : false;
}
void add(int &a, int b) {
    a += b;
    if (a >= mod) a -= mod;
    if (a < 0) a += mod;
}

int n;
vector<int> adj[N];
int state[N];

int f[N][2][2];

/*
f[u][i][j] : minimum number of moves to turn off subtree u
i = 0/1 if we toggle p
j = 0/1 if we toggle u
*/

void dfs(int u, int p) {
    for (int i = 0; i < 2; ++i) {
        f[u][i][state[u] ^ i] = i;
        f[u][i][state[u] ^ i ^ 1] = oo;
    }

    for (int v : adj[u]) if (v != p) {
        dfs(v, u);

        for (int i = 0; i < 2; ++i) {
            int even = f[u][i][0];
            int odd = f[u][i][1];
            
            f[u][i][0] = min({oo, even + f[v][0][i], odd + f[v][1][i]});
            f[u][i][1] = min({oo, even + f[v][1][i], odd + f[v][0][i]});
        }

    }
}

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

    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);

    cin >> n;
    for (int i = 1; i < n; ++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 >> state[i];

    dfs(1, 0);

    int ans = min(f[1][0][0], f[1][1][0]);
    if (ans == oo) return cout << "impossible", 0;
    cout << ans;

    return 0;
}

/*

*/

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 26712 KB Output is correct
2 Correct 6 ms 26920 KB Output is correct
3 Correct 7 ms 26716 KB Output is correct
4 Correct 6 ms 26716 KB Output is correct
5 Correct 6 ms 26716 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 26712 KB Output is correct
2 Correct 6 ms 26920 KB Output is correct
3 Correct 7 ms 26716 KB Output is correct
4 Correct 6 ms 26716 KB Output is correct
5 Correct 6 ms 26716 KB Output is correct
6 Correct 6 ms 26716 KB Output is correct
7 Correct 6 ms 26716 KB Output is correct
8 Correct 6 ms 26716 KB Output is correct
9 Correct 7 ms 26844 KB Output is correct
10 Correct 6 ms 26716 KB Output is correct
11 Correct 6 ms 26716 KB Output is correct
12 Correct 6 ms 26716 KB Output is correct
13 Correct 7 ms 26716 KB Output is correct
14 Correct 7 ms 26804 KB Output is correct
15 Correct 6 ms 26716 KB Output is correct
16 Correct 6 ms 26716 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 42920 KB Output is correct
2 Correct 41 ms 42584 KB Output is correct
3 Correct 43 ms 42792 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 44 ms 42832 KB Output is correct
2 Correct 52 ms 42832 KB Output is correct
3 Correct 41 ms 42832 KB Output is correct
4 Correct 35 ms 33104 KB Output is correct
5 Correct 38 ms 33364 KB Output is correct
6 Correct 37 ms 33372 KB Output is correct
7 Correct 6 ms 26716 KB Output is correct
8 Correct 16 ms 30876 KB Output is correct
9 Correct 42 ms 33620 KB Output is correct
10 Correct 39 ms 33524 KB Output is correct
11 Correct 40 ms 34060 KB Output is correct
12 Correct 37 ms 34384 KB Output is correct
13 Correct 34 ms 33368 KB Output is correct
14 Correct 39 ms 33364 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 26712 KB Output is correct
2 Correct 6 ms 26920 KB Output is correct
3 Correct 7 ms 26716 KB Output is correct
4 Correct 6 ms 26716 KB Output is correct
5 Correct 6 ms 26716 KB Output is correct
6 Correct 6 ms 26716 KB Output is correct
7 Correct 6 ms 26716 KB Output is correct
8 Correct 6 ms 26716 KB Output is correct
9 Correct 7 ms 26844 KB Output is correct
10 Correct 6 ms 26716 KB Output is correct
11 Correct 6 ms 26716 KB Output is correct
12 Correct 6 ms 26716 KB Output is correct
13 Correct 7 ms 26716 KB Output is correct
14 Correct 7 ms 26804 KB Output is correct
15 Correct 6 ms 26716 KB Output is correct
16 Correct 6 ms 26716 KB Output is correct
17 Correct 40 ms 42920 KB Output is correct
18 Correct 41 ms 42584 KB Output is correct
19 Correct 43 ms 42792 KB Output is correct
20 Correct 44 ms 42832 KB Output is correct
21 Correct 52 ms 42832 KB Output is correct
22 Correct 41 ms 42832 KB Output is correct
23 Correct 35 ms 33104 KB Output is correct
24 Correct 38 ms 33364 KB Output is correct
25 Correct 37 ms 33372 KB Output is correct
26 Correct 6 ms 26716 KB Output is correct
27 Correct 16 ms 30876 KB Output is correct
28 Correct 42 ms 33620 KB Output is correct
29 Correct 39 ms 33524 KB Output is correct
30 Correct 40 ms 34060 KB Output is correct
31 Correct 37 ms 34384 KB Output is correct
32 Correct 34 ms 33368 KB Output is correct
33 Correct 39 ms 33364 KB Output is correct
34 Correct 6 ms 26712 KB Output is correct
35 Correct 6 ms 26968 KB Output is correct
36 Correct 6 ms 26716 KB Output is correct
37 Correct 6 ms 26716 KB Output is correct
38 Correct 6 ms 26808 KB Output is correct
39 Correct 6 ms 26716 KB Output is correct
40 Correct 6 ms 26716 KB Output is correct
41 Correct 6 ms 26920 KB Output is correct
42 Correct 6 ms 26716 KB Output is correct
43 Correct 6 ms 26836 KB Output is correct
44 Correct 6 ms 26712 KB Output is correct
45 Correct 41 ms 42836 KB Output is correct
46 Correct 43 ms 42576 KB Output is correct
47 Correct 40 ms 42804 KB Output is correct
48 Correct 41 ms 33048 KB Output is correct
49 Correct 37 ms 33360 KB Output is correct
50 Correct 51 ms 33360 KB Output is correct
51 Correct 6 ms 26716 KB Output is correct
52 Correct 18 ms 30700 KB Output is correct
53 Correct 37 ms 33364 KB Output is correct
54 Correct 38 ms 33572 KB Output is correct
55 Correct 37 ms 34304 KB Output is correct
56 Correct 39 ms 34388 KB Output is correct
57 Correct 48 ms 33292 KB Output is correct
58 Correct 56 ms 33424 KB Output is correct
59 Correct 16 ms 30556 KB Output is correct
60 Correct 35 ms 33108 KB Output is correct
61 Correct 37 ms 33516 KB Output is correct
62 Correct 39 ms 33708 KB Output is correct
63 Correct 49 ms 33620 KB Output is correct
64 Correct 38 ms 33548 KB Output is correct
65 Correct 34 ms 34140 KB Output is correct
66 Correct 34 ms 33980 KB Output is correct
67 Correct 32 ms 33932 KB Output is correct
68 Correct 32 ms 33860 KB Output is correct
69 Correct 32 ms 34244 KB Output is correct
70 Correct 32 ms 33996 KB Output is correct