Submission #1182315

#	Time	Username	Problem	Language	Result	Execution time	Memory
1182315		qwusha	Village (BOI20_village)	C++20	56 / 100	45 ms	21064 KiB

Village

#include <bits/stdc++.h>
using namespace std;
/*
#pragma GCC optimize("O3")
#include <bitset>
#pragma GCC target("avx2")*/
#define fi first
#define se second
#define int long long
typedef long long ll;
typedef long double ld;
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
int inf = 1e15;

vector<vector<int>> g;
vector<int> used;
vector<int> gto, cfrom;
int res = 0;

void dfs(int v, int p = -1) {
    vector<int> s;
    for (auto u : g[v]) {
        if (u == p)
            continue;
        dfs(u, v);
        if (!used[u])
            s.push_back(u);
    }
    if (s.size() != 0) {
        res += s.size() * 2;
        used[v] = 1;
        gto[v] = s[0];
        cfrom[v] = s[s.size() - 1];
        gto[s[s.size() - 1]] = v;
        cfrom[s[0]] = v;
        for (int i = 0; i < s.size() - 1; i++) {
            gto[s[i]] = s[i + 1];
            cfrom[s[i + 1]] = s[i];
        }
    } else if (s.size() == 0 && p == -1) {
        res += 2;
        int u = g[v][0];
        gto[v] = u;
        gto[cfrom[u]] = v;
        cfrom[v] = cfrom[u];
        cfrom[u] = v;
    }
}


vector<vector<int>> dist;

void dfs_dist(int v, int st, int d = 0, int p =-1) {
    dist[v][st] = d;
    for (auto u : g[v]) {
        if (u != p) {
            dfs_dist(u, st, d + 1, v);
        }
    }
}



signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n;
    cin >> n;
    used.resize(n);
    g.resize(n);
    gto.resize(n);
    cfrom.resize(n);
    for (int i = 0; i < n - 1; i++) {
        int v, u;
        cin >> v >> u;
        g[v - 1].push_back(u - 1);
        g[u - 1].push_back(v - 1);
    }
    dfs(0);
    if (n <= 10) {
        dist.resize(n, vector<int>(n));
        for (int i = 0; i < n; i++) {
            dfs_dist(i, i);
        }
        int maxi = -1;
        vector<int> best;
        vector<int> p(n);
        for (int i = 0; i < n; i++)
            p[i] = i;
        do {
            int rs = 0;
            for (int i = 0; i < n; i++) {
                if (p[i] == i)
                    rs = -1;
                else if (rs != -1) {
                    rs += dist[i][p[i]];
                }
            }
            if (rs > maxi) {
                maxi = rs;
                best = p;
            }
        }
        while(next_permutation(p.begin(), p.end()));
        int rs = 0;
        for (int i = 0; i < n; i++) {
            if (p[i] == i)
                rs = -1;
            else if (rs != -1) {
                rs += dist[i][p[i]];
            }
        }
        if (rs > maxi) {
            maxi = rs;
            best = p;
        }
        cout << res << ' ' << maxi << '\n';
        for (int i = 0; i < n; i++) {
            cout << gto[i] + 1 << ' ';
        }
        cout << '\n';
        for (int i = 0; i < n; i++) {
            cout << best[i] + 1 << ' ';
        }
        cout << '\n';
        return 0;
    }
    cout << res << ' ' << 1 << '\n';
    for (int i = 0; i < n; i++) {
        cout << gto[i] + 1 << ' ';
    }
    cout << '\n';
    for (int i = 0; i < n; i++) {
        cout << 1 << ' ';
    }
    cout << '\n';
}

• Subtask 1: 12 / 12
• Subtask 2: 19 / 38
• Subtask 3: 25 / 50