Submission #574278

#	Time	Username	Problem	Language	Result	Execution time	Memory
574278		tengiz05	Village (BOI20_village)	C++17	100 / 100	128 ms	25524 KiB

Village

#include <bits/stdc++.h>

using i64 = long long;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int n;
    std::cin >> n;
    
    std::vector<std::vector<int>> adj(n);
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        std::cin >> u >> v;
        u--;
        v--;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    
    int mn = 0;
    
    std::vector<int> w(n, -1), o(n, -1);
    std::vector<int> siz(n, 1);
    
    std::function<void(int, int)> dfs = [&](int u, int p) {
        std::vector<int> a;
        int x = -1;
        for (int v : adj[u]) {
            if (v == p)
                continue;
            dfs(v, u);
            siz[u] += siz[v];
            if (w[v] == -1) {
                a.push_back(v);
            }
            x = v;
        }
        int m = a.size();
        if (m % 2 == 1) {
            for (int i = 0; i < m - 2; i += 2) {
                mn += 4;
                w[a[i]] = a[i + 1];
                w[a[i + 1]] = a[i];
            }
            mn += 2;
            w[u] = a[m - 1];
            w[a[m - 1]] = u;
        } else {
            for (int i = 0; i < m; i += 2) {
                mn += 4;
                w[a[i]] = a[i + 1];
                w[a[i + 1]] = a[i];
            }
            if (m >= 2) {
                w[u] = a[0];
                w[a[0]] = a[1];
                w[a[1]] = u;
            } else if (p == -1) {
                mn += 2;
                w[u] = w[x];
                w[x] = u;
            }
        }
    };
    
    dfs(0, -1);
    
    std::function<int(int, int)> dfs2 = [&](int u, int p) {
        for (int v : adj[u]) {
            if (v != p && siz[v] > n / 2) {
                return dfs2(v, u);
            }
        }
        return u;
    };
    
    int u = dfs2(0, -1);
    
    i64 mx = 0;
    
    std::vector<std::vector<int>> a(n);
    
    std::priority_queue<std::pair<int, int>> q;
    
    for (int v : adj[u]) {
        std::vector<int> b;
        std::function<void(int, int, int)> dfs = [&](int u, int p, int dep) {
            b.push_back(u);
            mx += dep;
            for (int v : adj[u]) {
                if (v != p) {
                    dfs(v, u, dep + 1);
                }
            }
        };
        dfs(v, u, 1);
        a[v] = b;
        q.emplace(b.size(), v);
    }
    
    while (q.size() > 1) {
        auto [si, i] = q.top();
        q.pop();
        auto [sj, j] = q.top();
        q.pop();
        o[a[i].back()] = a[j].back();
        o[a[j].back()] = a[i].back();
        a[i].pop_back();
        a[j].pop_back();
        if (si > 1) {
            q.emplace(si - 1, i);
        }
        if (sj > 1) {
            q.emplace(sj - 1, j);
        }
    }
    
    if (q.empty()) {
        int v = adj[u][0];
        o[u] = o[v];
        o[v] = u;
    } else {
        auto [si, i] = q.top();
        assert(a[i].size() == 1);
        o[u] = a[i][0];
        o[a[i][0]] = u;
    }
    
    std::cout << mn << " " << 2 * mx << "\n";
    
    for (int i = 0; i < n; i++) {
        std::cout << w[i] + 1 << " \n"[i == n - 1];
    }
    
    for (int i = 0; i < n; i++) {
        std::cout << o[i] + 1 << " \n"[i == n - 1];
    }
    
    return 0;
}

• Subtask 1: 12 / 12
• Subtask 2: 38 / 38
• Subtask 3: 50 / 50