Submission #257799

#	Time	Username	Problem	Language	Result	Execution time	Memory
257799		VEGAnn	Village (BOI20_village)	C++14	100 / 100	122 ms	15856 KiB

Village

#include <bits/stdc++.h>
#define sz(x) ((int)x.size())
#define PB push_back
#define i2 array<int,2>
using namespace std;
typedef long long ll;
const int N = 100100;
const int oo = 2e9;
set<i2> setik, oth;
vector<int> g[N], vc;
int n, siz[N], cen, who_kto[N], mrk[N];
ll ans, ANS;

void dfs(int v, int p){
    for (int u : g[v]){
        if (u == p) continue;

        dfs(u, v);

        if (mrk[u] < 0){
            ANS += 2;

            if (mrk[v] < 0){
                mrk[v] = u;
                mrk[u] = v;
            } else {
                mrk[u] = mrk[v];
                mrk[v] = u;
            }
        }
    }
}

void build_sz(int v, int p){
    siz[v] = 1;

    for (int u : g[v]){
        if (u == p) continue;

        build_sz(u, v);

        siz[v] += siz[u];

        ans += min(siz[u], n - siz[u]);
    }
}

int search(int v, int p, int SZ){
    for (int u : g[v])
        if (u != p && siz[u] > SZ / 2)
            return search(u, v, SZ);
    return v;
}

void add(int v, int p){
    vc.PB(v);

    for (int u : g[v]){
        if (u == p) continue;

        add(u, v);
    }
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);

#ifdef _LOCAL
    freopen("in.txt","r",stdin);
#endif // _LOCAL

    cin >> n;

    for (int i = 1; i < n; i++){
        int x, y; cin >> x >> y;
        x--; y--;

        g[x].PB(y);
        g[y].PB(x);
    }

    fill(mrk, mrk + n, -1);

    dfs(0, -1);

    if (mrk[0] < 0) {
        ANS += 2;

        mrk[0] = mrk[g[0][0]];
        mrk[g[0][0]] = 0;
    }

    build_sz(0, -1);

    cout << ANS << " " << ans * 2 << '\n';

    for (int i = 0; i < n; i++)
        who_kto[mrk[i]] = i;

    for (int i = 0; i < n; i++)
        cout << who_kto[i] + 1 << " ";
    cout << '\n';

    cen = search(0, -1, siz[0]);

    for (int u : g[cen])
        add(u, cen);

    vc.PB(cen);

    for (int i = 0; i < n; i++)
        who_kto[vc[i]] = vc[(i + n / 2) % n];

    for (int i = 0; i < n; i++)
        cout << who_kto[i] + 1 << " ";

    return 0;
}

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