Submission #596346

#	Time	Username	Problem	Language	Result	Execution time	Memory
596346		keta_tsimakuridze	Meetings 2 (JOI21_meetings2)	C++14	0 / 100	7 ms	9792 KiB

meetings2

#include<bits/stdc++.h>
#define f first
#define s second
#define pii pair<int,int>
#define Pii pair<pair<int,int> , pair<int,int> >
using namespace std;
const int N = 2e5 + 5, mod = 1e9 + 7; // !
int t, sz[N], f[N], h;
int n;
int ans[N];
vector< pair<int,int> > x[N];
vector<int> V[N];
int find(int u,int p, int Sz) {
    for(int i = 0; i< V[u].size(); i++) {
        if(V[u][i] == p|| f[V[u][i]]) continue;
        if(sz[V[u][i]] > Sz / 2) return find(V[u][i], u, Sz);
    }
    return u;
}
void dfs(int u, int p) {
    sz[u] = 1;
    for(int i = 0; i < V[u].size(); i++) {
        if(V[u][i] == p || f[V[u][i]]) continue;
        dfs(V[u][i], u);
        sz[u] += sz[V[u][i]];
    }
}
void dfs(int u,int p,int P) {
    ++h;
    x[sz[u]].push_back({h, P});
    ans[min(sz[u], n - sz[P]) * 2] = max(ans[min(sz[u], n - sz[P]) * 2], h + 1);
    for(int i = 0; i < V[u].size(); i++) {
        if(V[u][i] == p|| f[V[u][i]]) continue;
        dfs(V[u][i], u, P);
    }
    --h;
}
void upd(Pii &mx, pii x) {
    if(mx.f.f <= x.f) swap(mx.f, mx.s), mx.f = x;
    else mx.s = max(mx.s, x);
}
void decomp(int U) {
    dfs(U, 0);
    int c = find(U, 0, sz[U]);dfs(c, 0);
    for(int i = 0; i < V[c].size(); i++) {
        if(f[V[c][i]] == 0) dfs(V[c][i], c, V[c][i]);
    }

    pair<pii, pii> mx;
    mx = {{-n, 0}, {-n, 0}};
    for(int i = sz[c]; i >= 1; i--) {
        while(x[i].size()) {
            pii y = x[i].back();
            ans[i * 2] = max(ans[i * 2], y.f + (mx.f.s != y.s ? mx.f.f : mx.s.f ) + 1);
            upd(mx, y);
            x[i].pop_back();
        }
    }
    f[c] = 1;

    for(int i = 0; i < V[c].size(); i++) {
        if(!f[V[c][i]])  decomp(V[c][i]);
    }
}
main(){
    cin >> n;
    for(int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        V[u].push_back(v);
        V[v].push_back(u);
    }
    decomp(1);
    for(int i = n; i >= 1; i--) {
        ans[i] = (i % 2 == 0 ? max(ans[i], ans[i + 2]) : 1);
    }
    for(int i = 1; i <= n; i++) {
        cout << ans[i] << "\n";
    }
 }

Compilation message (stderr)

meetings2.cpp: In function 'int find(int, int, int)':
meetings2.cpp:14:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |     for(int i = 0; i< V[u].size(); i++) {
      |                    ~^~~~~~~~~~~~~
meetings2.cpp: In function 'void dfs(int, int)':
meetings2.cpp:22:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |     for(int i = 0; i < V[u].size(); i++) {
      |                    ~~^~~~~~~~~~~~~
meetings2.cpp: In function 'void dfs(int, int, int)':
meetings2.cpp:32:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 |     for(int i = 0; i < V[u].size(); i++) {
      |                    ~~^~~~~~~~~~~~~
meetings2.cpp: In function 'void decomp(int)':
meetings2.cpp:45:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |     for(int i = 0; i < V[c].size(); i++) {
      |                    ~~^~~~~~~~~~~~~
meetings2.cpp:61:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     for(int i = 0; i < V[c].size(); i++) {
      |                    ~~^~~~~~~~~~~~~
meetings2.cpp: At global scope:
meetings2.cpp:65:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   65 | main(){
      | ^~~~

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