Submission #1170042

#	Time	Username	Problem	Language	Result	Execution time	Memory
1170042		SmuggingSpun	Meetings 2 (JOI21_meetings2)	C++20	0 / 100	0 ms	332 KiB

meetings2

#include<bits/stdc++.h>
#define taskname "C"
using namespace std;
const int lim = 2e5 + 5;
const int INF = 1e9;
template<class T>bool minimize(T& a, T b){
    if(a > b){
        a = b;
        return true;
    }
    return false;
}
template<class T>void maximize(T& a, T b){
    if(a < b){
        a = b;
    }
}
int n;
namespace sub1{
    void solve(){
        vector<vector<int>>g(n);
        for(int i = 1; i < n; i++){
            int u, v;
            cin >> u >> v;
            g[--u].emplace_back(--v);
            g[v].emplace_back(u);
        }
        vector<vector<int>>d(n, vector<int>(n, -1));
        for(int i = 0; i < n; i++){
            queue<int>q;
            q.push(i);
            d[i][i] = 0;
            while(!q.empty()){
                int u = q.front();
                q.pop();
                for(int& v : g[u]){
                    if(d[i][v] == -1){
                        d[i][v] = d[i][u] + 1;
                        q.push(v);
                    }
                }
            }
        }
        vector<int>ans(n + 1, 0);
        for(int mask = (1 << n) - 1; mask > 0; mask--){
            vector<int>p;
            for(int i = 0; i < n; i++){
                if(1 << i & mask){
                    p.emplace_back(i);
                }
            }
            int cnt = 0, opt = INF;
            for(int i = 0; i < n; i++){
                int distance = 0;
                for(int& j : p){
                    distance += d[i][j];
                }
                if(minimize(opt, distance)){
                    cnt = 0;
                }
                if(opt == distance){
                    cnt++;
                }
            }
            maximize(ans[p.size()], cnt);
        }
        for(int i = 1; i <= n; i++){
            cout << ans[i] << "\n";
        }
    }
}
namespace sub2{
    void solve(){
        vector<vector<int>>g(n + 1);
        for(int i = 1; i < n; i++){
            int u, v;
            cin >> u >> v;
            g[u].emplace_back(v);
            g[v].emplace_back(u);
        }
        vector<int>ans(n + 1, 1), cnt_child(n + 1, 1), parent(n + 1), h(n + 1);
        function<void(int)>dfs;
        dfs = [&] (int s){
            for(int& d : g[s]){
                if(d != parent[s]){
                    h[d] = h[parent[d] = s] + 1;
                    dfs(d);
                    cnt_child[s] += cnt_child[d];
                }
            }
        };
        parent[1] = h[1] = 0;
        dfs(1);
        for(int i = 1; i <= n; i++){
            int j = i, k = i;
            while(j != 0){
                maximize(ans[min(cnt_child[i], n - cnt_child[k]) << 1], h[i] - h[j] + 1);
                j = parent[k = j];
            }
        }
        for(int i = n - (n & 1) - 2; i > 0; i--){
            maximize(ans[i], ans[i + 2]);
        }
        for(int i = 1; i <= n; i++){
            cout << ans[i] << "\n";
        }
    }
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
    cin >> n;
    if(n <= 16){
        sub2::solve();
    }
    else if(n <= 4000){
        sub2::solve();
    }
}

Compilation message (stderr)

meetings2.cpp: In function 'int main()':
meetings2.cpp:112:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  112 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 16
• Subtask 3: 0 / 80