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Submission #933893

# Submission time Handle Problem Language Result Execution time Memory
933893 2024-02-26T14:00:28 Z codefox The Xana coup (BOI21_xanadu) C++14
100 / 100
 61 ms 28496 KB 
#include<bits/stdc++.h>

using namespace std;

#define pii pair<int, int>
#define arr array<int, 2>
#define int long long

int inf = 1e9;

vector<vector<int>> graph;
vector<int> state;
vector<array<arr, 2>> opt;

void dfs(int i, int p)
{
    opt[i][0][0] = inf;
    opt[i][0][1] = inf;
    opt[i][1][0] = inf;
    opt[i][1][1] = inf;

    if (graph[i].size() == 1 && i != 0)
    {
        int s = state[i];
        opt[i][s][0] = 0;
        opt[i][s][1] = inf;
        if (s == 1) s = 0;
        else s = 1;
        opt[i][s][0] = inf;
        opt[i][s][1] = 1;
        return;
    }
    vector<int> on;
    vector<int> off; 
    int sumon = 0;
    int sumoff = 0;
    for (int ele:graph[i])
    {
        if (ele == p) continue;
        dfs(ele, i);

        sumon += opt[ele][1][0];
        on.push_back(opt[ele][1][1]-opt[ele][1][0]);

        sumoff += opt[ele][0][0];
        off.push_back(opt[ele][0][1]-opt[ele][0][0]);
    }
    sort(on.begin(), on.end(), less<int>());
    sort(off.begin(), off.end(), less<int>());

    int s = state[i];
    int ns;
    if (s == 0) ns = 1;
    else ns = 0;


    for (int j = 0; j <= on.size(); j++)
    {
        if (j%2) opt[i][s][1] = min(opt[i][s][1], sumon+1); 
        else opt[i][ns][1] = min(opt[i][ns][1], sumon+1);
        if (j < on.size()) sumon+=on[j];
    }

    for (int j = 0; j <= off.size(); j++)
    {
        if (j%2) opt[i][ns][0] = min(opt[i][ns][0], sumoff); 
        else opt[i][s][0] = min(opt[i][s][0], sumoff);
        if (j < off.size()) sumoff+=off[j];
    }
}

int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);

    int n;
    cin >> n;
    graph.assign(n, vector<int>());
    state.assign(n, 0);
    opt.assign(n, array<arr, 2>());
    
    for (int i = 1; i < n; i++)
    {
        int a, b;
        cin >> a >> b;
        a--; b--;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    for (int i = 0; i < n; i++) cin >> state[i];

    dfs(0, -1);

    /*
    for (int i = 0; i < n; i++)
    {
        cout << opt[i][0][0] << " " << opt[i][0][1] << endl;
        cout << opt[i][1][0] << " " << opt[i][1][1] << endl;
    }
    */

    int mn = min(opt[0][0][0], opt[0][0][1]);
    if (mn > n) cout << "impossible\n";
    else cout << mn << "\n";

    return 0;
}

Compilation message

xanadu.cpp: In function 'void dfs(long long int, long long int)':
xanadu.cpp:57:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |     for (int j = 0; j <= on.size(); j++)
      |                     ~~^~~~~~~~~~~~
xanadu.cpp:61:15: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |         if (j < on.size()) sumon+=on[j];
      |             ~~^~~~~~~~~~~
xanadu.cpp:64:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |     for (int j = 0; j <= off.size(); j++)
      |                     ~~^~~~~~~~~~~~~
xanadu.cpp:68:15: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |         if (j < off.size()) sumoff+=off[j];
      |             ~~^~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 460 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 0 ms 344 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 1 ms 452 KB Output is correct
15 Correct 0 ms 456 KB Output is correct
16 Correct 0 ms 348 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 60 ms 26964 KB Output is correct
2 Correct 48 ms 26452 KB Output is correct
3 Correct 48 ms 26960 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 50 ms 26704 KB Output is correct
2 Correct 50 ms 26452 KB Output is correct
3 Correct 47 ms 26972 KB Output is correct
4 Correct 36 ms 9560 KB Output is correct
5 Correct 53 ms 11808 KB Output is correct
6 Correct 44 ms 11868 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 13 ms 4336 KB Output is correct
9 Correct 42 ms 11700 KB Output is correct
10 Correct 42 ms 11868 KB Output is correct
11 Correct 41 ms 12740 KB Output is correct
12 Correct 44 ms 13144 KB Output is correct
13 Correct 39 ms 11612 KB Output is correct
14 Correct 50 ms 12376 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 460 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 0 ms 344 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 1 ms 452 KB Output is correct
15 Correct 0 ms 456 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 60 ms 26964 KB Output is correct
18 Correct 48 ms 26452 KB Output is correct
19 Correct 48 ms 26960 KB Output is correct
20 Correct 50 ms 26704 KB Output is correct
21 Correct 50 ms 26452 KB Output is correct
22 Correct 47 ms 26972 KB Output is correct
23 Correct 36 ms 9560 KB Output is correct
24 Correct 53 ms 11808 KB Output is correct
25 Correct 44 ms 11868 KB Output is correct
26 Correct 1 ms 348 KB Output is correct
27 Correct 13 ms 4336 KB Output is correct
28 Correct 42 ms 11700 KB Output is correct
29 Correct 42 ms 11868 KB Output is correct
30 Correct 41 ms 12740 KB Output is correct
31 Correct 44 ms 13144 KB Output is correct
32 Correct 39 ms 11612 KB Output is correct
33 Correct 50 ms 12376 KB Output is correct
34 Correct 0 ms 348 KB Output is correct
35 Correct 0 ms 348 KB Output is correct
36 Correct 1 ms 344 KB Output is correct
37 Correct 0 ms 348 KB Output is correct
38 Correct 0 ms 348 KB Output is correct
39 Correct 0 ms 348 KB Output is correct
40 Correct 0 ms 348 KB Output is correct
41 Correct 0 ms 348 KB Output is correct
42 Correct 1 ms 596 KB Output is correct
43 Correct 0 ms 348 KB Output is correct
44 Correct 0 ms 344 KB Output is correct
45 Correct 48 ms 28244 KB Output is correct
46 Correct 47 ms 27852 KB Output is correct
47 Correct 48 ms 28496 KB Output is correct
48 Correct 42 ms 10576 KB Output is correct
49 Correct 49 ms 11672 KB Output is correct
50 Correct 45 ms 11984 KB Output is correct
51 Correct 0 ms 344 KB Output is correct
52 Correct 13 ms 4188 KB Output is correct
53 Correct 61 ms 11604 KB Output is correct
54 Correct 42 ms 11860 KB Output is correct
55 Correct 42 ms 12860 KB Output is correct
56 Correct 45 ms 13228 KB Output is correct
57 Correct 37 ms 11612 KB Output is correct
58 Correct 49 ms 12380 KB Output is correct
59 Correct 15 ms 4188 KB Output is correct
60 Correct 38 ms 10556 KB Output is correct
61 Correct 54 ms 11348 KB Output is correct
62 Correct 41 ms 11608 KB Output is correct
63 Correct 40 ms 11836 KB Output is correct
64 Correct 41 ms 11864 KB Output is correct
65 Correct 39 ms 12124 KB Output is correct
66 Correct 39 ms 12124 KB Output is correct
67 Correct 35 ms 14280 KB Output is correct
68 Correct 35 ms 14280 KB Output is correct
69 Correct 34 ms 14300 KB Output is correct
70 Correct 40 ms 14180 KB Output is correct