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Submission #405775

# Submission time Handle Problem Language Result Execution time Memory
405775 2021-05-16T21:58:34 Z 534351 The Xana coup (BOI21_xanadu) C++17
100 / 100
 94 ms 16496 KB 
#include <bits/stdc++.h>

using namespace std;

template<class T, class U>
void ckmin(T &a, U b)
{
    if (a > b) a = b;
}

template<class T, class U>
void ckmax(T &a, U b)
{
    if (a < b) a = b;
}

#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)
#define SZ(x) ((int) (x).size())
#define ALL(x) (x).begin(), (x).end()

const int MAXN = 1e5 + 13;
const int INF = 1e9 + 7;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpi;
typedef vector<pll> vpl;
typedef array<array<int, 2>, 2> dparr;

int N;
vi edge[MAXN];
bitset<MAXN> flip;
dparr dp[MAXN]; //current state of vtx, whether vtx has been flipped.
int ans;

dparr comb(dparr l, dparr r)
{
    dparr res;
    FOR(i, 0, 2) FOR(j, 0, 2) res[i][j] = INF;
    FOR(i, 0, 2)
    {
        FOR(j, 0, 2)
        {
            FOR(k, 0, 2)
            {
                ckmin(res[k ^ j][i], r[i][j] + l[k][i]);
            }
        }
    }
    return res;
}
void dfs(int u, int p)
{
    for (int v : edge[u])
    {
        if (v == p) continue;
        dfs(v, u);
    }
    FOR(i, 0, 2)
    {
        FOR(j, 0, 2)
        {
            dp[u][i][j] = INF;
        }
    }
    dp[u][flip[u] ^ 1][1] = 1;
    dp[u][flip[u]][0] = 0;
    for (int v : edge[u])
    {
        if (v == p) continue;
        dp[u] = comb(dp[u], dp[v]);
    }
    return;
}

int32_t main()
{
    ios_base::sync_with_stdio(false); cin.tie(0);
    cout << fixed << setprecision(12);
    cerr << fixed << setprecision(4);
    cin >> N;
    FOR(i, 0, N - 1)
    {
        int u, v;
        cin >> u >> v; u--; v--;
        edge[u].PB(v);
        edge[v].PB(u);
    }
    FOR(i, 0, N)
    {
        bool b; cin >> b;
        flip[i] = b;
    }
    dfs(0, N);
    ans = min(dp[0][0][1], dp[0][0][0]);
    if (ans == INF)
    {
        cout << "impossible\n";
        return 0;
    }
    cout << ans << '\n';
    return 0;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 2 ms 2664 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 2 ms 2664 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 2 ms 2636 KB Output is correct
8 Correct 3 ms 2668 KB Output is correct
9 Correct 2 ms 2636 KB Output is correct
10 Correct 2 ms 2636 KB Output is correct
11 Correct 3 ms 2636 KB Output is correct
12 Correct 3 ms 2664 KB Output is correct
13 Correct 3 ms 2672 KB Output is correct
14 Correct 3 ms 2636 KB Output is correct
15 Correct 2 ms 2636 KB Output is correct
16 Correct 2 ms 2636 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 63 ms 16428 KB Output is correct
2 Correct 66 ms 16240 KB Output is correct
3 Correct 66 ms 16496 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 71 ms 16376 KB Output is correct
2 Correct 73 ms 16248 KB Output is correct
3 Correct 65 ms 16480 KB Output is correct
4 Correct 62 ms 8004 KB Output is correct
5 Correct 62 ms 8452 KB Output is correct
6 Correct 65 ms 8608 KB Output is correct
7 Correct 3 ms 2636 KB Output is correct
8 Correct 20 ms 4684 KB Output is correct
9 Correct 78 ms 8644 KB Output is correct
10 Correct 70 ms 8676 KB Output is correct
11 Correct 76 ms 9148 KB Output is correct
12 Correct 83 ms 9340 KB Output is correct
13 Correct 58 ms 8260 KB Output is correct
14 Correct 75 ms 8616 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 2 ms 2664 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 2 ms 2636 KB Output is correct
8 Correct 3 ms 2668 KB Output is correct
9 Correct 2 ms 2636 KB Output is correct
10 Correct 2 ms 2636 KB Output is correct
11 Correct 3 ms 2636 KB Output is correct
12 Correct 3 ms 2664 KB Output is correct
13 Correct 3 ms 2672 KB Output is correct
14 Correct 3 ms 2636 KB Output is correct
15 Correct 2 ms 2636 KB Output is correct
16 Correct 2 ms 2636 KB Output is correct
17 Correct 63 ms 16428 KB Output is correct
18 Correct 66 ms 16240 KB Output is correct
19 Correct 66 ms 16496 KB Output is correct
20 Correct 71 ms 16376 KB Output is correct
21 Correct 73 ms 16248 KB Output is correct
22 Correct 65 ms 16480 KB Output is correct
23 Correct 62 ms 8004 KB Output is correct
24 Correct 62 ms 8452 KB Output is correct
25 Correct 65 ms 8608 KB Output is correct
26 Correct 3 ms 2636 KB Output is correct
27 Correct 20 ms 4684 KB Output is correct
28 Correct 78 ms 8644 KB Output is correct
29 Correct 70 ms 8676 KB Output is correct
30 Correct 76 ms 9148 KB Output is correct
31 Correct 83 ms 9340 KB Output is correct
32 Correct 58 ms 8260 KB Output is correct
33 Correct 75 ms 8616 KB Output is correct
34 Correct 2 ms 2636 KB Output is correct
35 Correct 2 ms 2636 KB Output is correct
36 Correct 2 ms 2636 KB Output is correct
37 Correct 2 ms 2668 KB Output is correct
38 Correct 2 ms 2636 KB Output is correct
39 Correct 2 ms 2636 KB Output is correct
40 Correct 3 ms 2668 KB Output is correct
41 Correct 3 ms 2636 KB Output is correct
42 Correct 2 ms 2664 KB Output is correct
43 Correct 2 ms 2668 KB Output is correct
44 Correct 2 ms 2636 KB Output is correct
45 Correct 63 ms 16328 KB Output is correct
46 Correct 66 ms 16196 KB Output is correct
47 Correct 76 ms 16476 KB Output is correct
48 Correct 59 ms 7976 KB Output is correct
49 Correct 69 ms 8672 KB Output is correct
50 Correct 74 ms 8676 KB Output is correct
51 Correct 3 ms 2636 KB Output is correct
52 Correct 20 ms 4684 KB Output is correct
53 Correct 71 ms 8600 KB Output is correct
54 Correct 66 ms 8688 KB Output is correct
55 Correct 66 ms 9088 KB Output is correct
56 Correct 74 ms 9336 KB Output is correct
57 Correct 60 ms 8244 KB Output is correct
58 Correct 71 ms 8588 KB Output is correct
59 Correct 22 ms 4652 KB Output is correct
60 Correct 58 ms 8032 KB Output is correct
61 Correct 65 ms 8548 KB Output is correct
62 Correct 90 ms 8864 KB Output is correct
63 Correct 70 ms 8788 KB Output is correct
64 Correct 94 ms 8680 KB Output is correct
65 Correct 59 ms 9292 KB Output is correct
66 Correct 57 ms 9160 KB Output is correct
67 Correct 48 ms 9048 KB Output is correct
68 Correct 54 ms 9124 KB Output is correct
69 Correct 48 ms 9084 KB Output is correct
70 Correct 51 ms 9116 KB Output is correct