Submission #970826

#	Time	Username	Problem	Language	Result	Execution time	Memory
970826		vjudge1	Meetings 2 (JOI21_meetings2)	C++17	100 / 100	406 ms	26308 KiB

meetings2

#include<bits/stdc++.h>

using namespace std;

int n, u, v, subtree[200005], ans[200005], l[200005], l2[200005];
vector<int> adj[200005];
bool rm[200005];

void build(int u, int par) {
    subtree[u] = 1;
    for (int node: adj[u]) {
        if(node == par || rm[node]) continue;
        build(node, u);
        subtree[u] += subtree[node];
    }
}

int centroid(int u, int par, int sz) {
    for (int node: adj[u]) {
        if(node == par || rm[node]) continue;
        if(subtree[node] > sz / 2) return centroid(node, u, sz);
    }
    return u;
}

void dfs(int u, int par, int dis) {
    l[subtree[u]] = max(l[subtree[u]], dis + 1);
    //cout << "CHECK " << u << ' ' << subtree[u] << ' ' << dis + 1 << '\n';
    for (int node: adj[u]) {
        if(node == par || rm[node]) continue;
        dfs(node, u, dis + 1);
    }
}

void build2(int u, int par) {
    subtree[u] = 1;
    for (int node: adj[u]) {
        if(node == par || rm[node]) continue;
        build2(node, u);
        subtree[u] += subtree[node];
    }
}

void solve(int u) {
    build(u, -1);
    int C = centroid(u, -1, subtree[u]);
    build2(C, -1);
    rm[C] = true;
    int mx = 0;
    //cout << "C: " << C << '\n';
    for (int i = 1; i <= subtree[C]; i++) l2[i] = 1;
    for (int node: adj[C]) {
        if(rm[node]) continue;
        dfs(node, C, 1);
        mx = max(mx, subtree[node] + 5);
        for (int i = subtree[node] - 1; i >= 1; i--) l[i] = max(l[i], l[i + 1]);
        //if(C == 1) cout << l[1] << ' ' << l2[1] << '\n';
        for (int i = subtree[node]; i >= 1; i--) {
            ans[i * 2] = max(ans[i * 2], l2[i] + l[i] - 1);
            l2[i] = max(l2[i], l[i]);
            l[i] = 0;
        }
    }
    for (int i = 1; i <= mx; i++) l2[i] = l[i] = 0;
    for (int node: adj[C]) {
        if(rm[node]) continue;
        solve(node);
    }
}

signed main() {
    //freopen("fact.inp", "r", stdin);
    //freopen("fact.out", "w", stdout);
    cin >> n;
    for (int i = 1; i < n; i++) {
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    solve(1);
    for (int i = 1; i <= n; i++) {
        ans[i] = max(ans[i], 1);
        if(i % 2 == 1) cout << 1 << '\n';
        else cout << ans[i] << '\n';
    }
}

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