Submission #986218

#	Time	Username	Problem	Language	Result	Execution time	Memory
986218		dorjderem	The Xana coup (BOI21_xanadu)	C++17	0 / 100	317 ms	524288 KiB

xanadu

#include <iostream>
#include <vector>
#include <queue>
#include <tuple>
#include <algorithm>

using namespace std;

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

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

    vector<int> state(n);
    for (int i = 0; i < n; ++i)
    {
        cin >> state[i];
    }

    bool found = false;
    for (int i = 0; i < n; ++i)
    {
        queue<pair<int, vector<int>>> q;
        q.push(make_pair(i, state));

        int level = 0;
        while (!q.empty() && level < 20)
        {
            int q_size = q.size();
            for (int j = 0; j < q_size; ++j)
            {
                auto front = q.front();
                q.pop();

                int node = front.first;
                vector<int> current_state = front.second;

                if (all_of(current_state.begin(), current_state.end(), [](bool v)
                           { return !v; }))
                {
                    cout << level << endl;
                    return 0;
                }

                current_state[node] = !current_state[node];
                for (int neighbor : adj[node])
                {
                    current_state[neighbor] = !current_state[neighbor];
                }

                for (int k = 0; k < n; ++k)
                {
                    if (k != node)
                    {
                        q.push(make_pair(k, current_state));
                    }
                }
            }
            ++level;
        }
    }

    if (!found)
    {
        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