Submission #1170073

#	Time	Username	Problem	Language	Result	Execution time	Memory
1170073		SmuggingSpun	Meetings 2 (JOI21_meetings2)	C++20	0 / 100	0 ms	328 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), h(n + 1);
        vector<vector<int>>up(n + 1, vector<int>(12, 0));
        function<void(int)>dfs;
        dfs = [&] (int s){
            for(int& d : g[s]){
                if(d != up[s][0]){
                    h[d] = h[up[d][0] = s] + 1;
                    for(int i = 1; i < 12; i++){
                        up[d][i] = up[up[d][i - 1]][i - 1];
                    }
                    dfs(d);
                    cnt_child[s] += cnt_child[d];
                }
            }
        };
        dfs(h[1] = 1);
        auto lca = [&] (int u, int v){
            for(int k = h[u] - h[v], i = 0; i < 12; i++){
                if(1 << i & k){
                    u = up[u][i];
                }
            }
            if(u == v){
                return u;
            }
            for(int i = 11; i > -1; i--){
                if(up[u][i] != up[v][i]){
                    u = up[u][i];
                    v = up[v][i];
                }
            }
            return u;
        };
        for(int i = 1; i <= n; i++){
            for(int j = i + 1; j <= n; j++){
                int u = i, v = j;
                if(h[u] < h[v]){
                    swap(u, v);
                }
                int z = lca(u, v);
                if(z == v){
                    int cnt = cnt_child[u], H = h[u];
                    for(int t = 0, k = h[u] - h[v] - 1; t < 12; t++){
                        if(1 << t & k){
                            u = up[u][t];
                        }
                    }
                    maximize(ans[min(cnt, n - cnt_child[u]) << 1], H - h[v] + 1);
                    continue;
                }
                maximize(ans[min(cnt_child[u], cnt_child[v]) << 1], h[u] + h[v] - (h[z] << 1) + 1);
            }
        }
        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:145:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  145 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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