Submission #896158

#	Time	Username	Problem	Language	Result	Execution time	Memory
896158		ShaShi	Village (BOI20_village)	C++17	50 / 100	56 ms	17836 KiB

Village

#include <bits/stdc++.h>
// #define int long long 
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define kill(x) cout << x << endl, exit(0);
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
 
 
using namespace std;
typedef long long ll;
typedef long double ld;
 
 
const int MAXN = (int)1e5 + 7;
const int MOD = 998244353;
const int INF = (int)1e9 + 7;
 
 
 
int n, m, t, flag, k, u, v, w, ans, ans2, tmp, tmp2, tmp3, tmp4;
int arr[MAXN], arr2[MAXN], par[MAXN], h[MAXN], sz[MAXN], cent;
int arr3[MAXN], arr4[MAXN];
vector<int> adj[MAXN];

bool DFS(int v, int p=-1) {
    bool res = 0;

    for (int u:adj[v]) {
        if (u != p) res |= DFS(u, v);
    }

    if (res) return 0;

    if (v != 1) {
        swap(arr[v], arr[p]);
        ans++;
        return 1;
    }

    swap(arr[1], arr[adj[1][0]]);
    ans++;
    return 0;
}


void DFSsz(int v, int p=-1) {
    sz[v] = 1;

    for (int u:adj[v]) {
        if (u == p) continue;
        DFSsz(u, v);
        sz[v] += sz[u];
    }
}


int centroid(int tot, int v, int p=-1) {
    for (int u:adj[v]) {
        if (u != p && 2*sz[u] > tot) {
            return centroid(tot, u, v);
        }
    }

    return v;
}



vector<int> vec, vec2;
vector<pii> love;

void DFS2(int v, int p=-1) {
    vec2.pb(v);
    
    for (int u:adj[v]) {
        if (u == p || u == cent) continue;
        DFS2(u, v);
    }
}


void solve() {
    vec.pb(cent);

    tmp4 = 1;

    for (int u:adj[cent]) {
        love.pb(mp(sz[u], u));
    }
    
    sort(all(love), greater<pii>());

    for (auto cur:love) {
        u = cur.S;
        // vec2.clear();
        DFS2(u);

        tmp4 += vec2.size();

        while (vec.size() && vec2.size()) {
            swap(arr3[vec.back()], arr3[vec2.back()]);
            vec2.pop_back();
            vec.pop_back();
        }

        while (vec2.size()) {
            vec.pb(vec2.back());
            vec2.pop_back();
        }
    }
}


int32_t main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
 
    cin >> n;

    for (int i=1; i<n; i++) {
        cin >> u >> v;

        adj[u].pb(v);
        adj[v].pb(u);
    }

    // Min 
    for (int i=1; i<=n; i++) arr[i] = i;
    DFS(1);
    for (int i=1; i<=n; i++) arr2[arr[i]] = i;

    // Max
    DFSsz(1);
    cent = centroid(n, 1);
    DFSsz(cent);
    for (int i=1; i<=n; i++) arr3[i] = i;
    solve();

    // cout << "!" << cent << endl;

    for (int i=1; i<=n; i++) if (i != cent) ans2 += sz[i];

    if (tmp4%2) ans2 = 0;

    cout << 2*ans << " " << 2*ans2 << endl;

    for (int i=1; i<=n; i++) cout << arr2[i] << " ";
    cout << endl;

    for (int i=1; i<=n; i++) cout << arr3[i] << " ";
    cout << endl;

 
    return 0;
}

• Subtask 1: 6 / 12
• Subtask 2: 19 / 38
• Subtask 3: 25 / 50