Submission #955661

#	Time	Username	Problem	Language	Result	Execution time	Memory
955661		Lukap	Meetings 2 (JOI21_meetings2)	C++14	100 / 100	605 ms	29132 KiB

meetings2

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int MAXN = 2e5 + 500;
const ll INF = 1e18;

int n;
vector<int> susjedi[MAXN], v;
int rj[2 * MAXN], bio[MAXN], d[MAXN], w[MAXN], flag[MAXN];

void dfs (int x, int p) {
    w[x] = 1;
    v.push_back (x);
    for (auto nx: susjedi[x]) {
        if (nx == p || bio[nx]) continue;
        d[nx] = d[x] + 1;
        dfs (nx, x);
        w[x] += w[nx];
    }
}

void postavi_flag (int x, int p, int r) {
    flag[x] = r;
    for (auto nx: susjedi[x]) {
        if (nx == p || bio[nx]) continue;
        postavi_flag(nx, x, r);
    }
}

bool cmp (int x, int y) {
    return w[x] > w[y];
}

void centroid (int x) {
    v.clear ();
    d[x] = 0;
    dfs (x, x);

    for (auto it: v) {
        bool dobro = true;
        for (auto nx: susjedi[it]) {
            if (bio[nx]) continue;
            if (d[it] < d[nx] && w[nx] > v.size () / 2) dobro = false;
            if (d[nx] < d[it] && v.size () - w[it] > v.size () / 2) dobro = false;
        }
        if (dobro) x = it;
    }
    v.clear ();
    d[x] = 0;
    dfs (x, x);

    for (auto it: susjedi[x]) {
        if (bio[it]) continue;
        postavi_flag (it, x, it);
    }

    for (auto it: v) {
        if (it == x) continue;
        int ind  = min (w[it], (int) v.size () - w[flag[it]]);
        rj[ind] = max (rj[ind], d[it] + 1);
    }
    v.erase (find (v.begin (), v.end (), x));
    sort (v.begin (), v.end (), cmp);

    int prvi = -1, drugi = -1;
    for (auto it: v) {
        if (prvi == -1) {
            prvi = it;
            continue;
        }
        else if (drugi == -1 && flag[it] != flag[prvi]) drugi = it;
        else if (drugi == -1 && flag[it] == flag[prvi] && d[it] > d[prvi]) {
            prvi = it;
            continue;
        }
        else if (drugi == -1 && flag[it] == flag[prvi]) continue;
        else if (d[it] > d[prvi] && flag[it] != flag[prvi]) {
            drugi = prvi;
            prvi = it;
        }
        else if (d[it] > d[prvi] && flag[it] == flag[prvi]) prvi = it;
        else if (d[it] > d[drugi] && flag[it] != flag[prvi]) drugi = it;

        int ind = min (w[prvi], w[drugi]);
        rj[ind] = max (rj[ind], d[prvi] + d[drugi] + 1);
    }


    bio[x] = 1;
    for (auto it: susjedi[x]) {
        if (!bio[it]) centroid (it);
    }
}

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

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

    for (int i = n; i > 0; i--) rj[i] = max (max (rj[i], rj[i + 1]), 1);
    for (int i = n; i > 0; i--) rj[2 * i] = rj[i];
    for (int i = 1; i <= n; i+= 2) rj[i] = 1;

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

    return 0;
}

Compilation message (stderr)

meetings2.cpp: In function 'void centroid(int)':
meetings2.cpp:46:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |             if (d[it] < d[nx] && w[nx] > v.size () / 2) dobro = false;
      |                                  ~~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 16 / 16
• Subtask 3: 80 / 80