Submission #986244

#	Time	Username	Problem	Language	Result	Execution time	Memory
986244		dorjderem	The Xana coup (BOI21_xanadu)	C++17	0 / 100	416 ms	524288 KiB

xanadu

#include <iostream>
#include <vector>
#include <queue>
#include <unordered_map>
#include <bitset>

using namespace std;

#define ull unsigned long long

int main()
{
    int n;
    cin >> n;

    vector<vector<int>> adj(n);
    int a, b;
    for (int i = 0; i < n - 1; ++i)
    {
        cin >> a >> b;
        --a;
        --b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }

    ull state = 0;
    for (int i = 0; i < n; ++i)
    {
        int temp;
        cin >> temp;
        if (temp == 1)
        {
            state |= (1ULL << i);
        }
    }

    queue<tuple<int, ull, ull>> q;
    for (int i = 0; i < n; i++)
        q.push(make_tuple(i, state, 0));

    int level = 0;
    while (!q.empty() && level <= n)
    {
        int q_size = q.size();
        for (int j = 0; j < q_size; ++j)
        {
            auto [node, current_state, visited_bits] = q.front();
            q.pop();
            if (current_state == 0)
            {
                cout << level << endl;
                return 0;
            }
            ull temp_state = current_state;
            temp_state ^= (1ULL << node);
            for (ull nxt : adj[node])
            {
                temp_state ^= (1ULL << nxt);
            }
            for (int k = 0; k < n; k++)
            {
                if ((visited_bits & (1ULL << k)) == 0)
                {
                    int temp_vis = visited_bits;
                    temp_vis |= (1 << k);
                    q.push(make_tuple(k, temp_state, temp_vis));
                }
            }
        }
        ++level;
    }

    cout << "IMPOSSIBLE" << endl;

    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 40
• Subtask 5: 0 / 30