Submission #725048

#	Time	Username	Problem	Language	Result	Execution time	Memory
725048		MohammadAghil	Meetings 2 (JOI21_meetings2)	C++17	100 / 100	403 ms	62060 KiB

meetings2

#include <bits/stdc++.h>
using namespace std;
#define rep(i,l,r) for(int i = (l); i < (r); i++)
#define per(i,r,l) for(int i = (r); i >= (l); i--)
#define all(x) begin(x), end(x)
#define sz(x) (int)size(x)
#define pb push_back
#define ff first
#define ss second
typedef long long ll;
typedef pair<int, int> pp;

void dbg(){
     cerr << endl;
}
template<typename H, typename... T> void dbg(H h, T... t){
     cerr << h << ", ";
     dbg(t...);
}

void IOS(){
     cin.tie(0) -> sync_with_stdio(0);
     #ifndef ONLINE_JUDGE
          // freopen("inp.txt", "r", stdin);
          // freopen("out.txt", "w", stdout);
          #define er(...) cerr << __LINE__ << " <" << #__VA_ARGS__ << ">: ", dbg(__VA_ARGS__)
     #else
          #define er(...) 0
     #endif
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const ll mod = 1e9 + 7, mod2 = 1e9 + 9, maxn = 5e5 + 5, lg = 21, inf = ll(1e18) + 5, p = 9973;

ll pw(ll a, ll b){
     if(b == 0) return 1;
     ll k = pw(a, b>>1);
     return k*k*(b&1ll?a:1);
}

vector<int> adj[maxn];
int cnt[maxn], par[maxn][lg], h[maxn];

void dfs(int r, int p){
     cnt[r] = 1;
     for(int c: adj[r]) if(c - p){
          dfs(c, r);
          cnt[r] += cnt[c];
     }
}

vector<int> srt[maxn];
void dfs2(int r, int p){
     cnt[r] = 1;
     par[r][0] = p;
     rep(i,1,lg) par[r][i] = par[par[r][i-1]][i-1];
     for(int c: adj[r]) if(c - p){
          h[c] = h[r] + 1;
          dfs2(c, r);
          cnt[r] += cnt[c];
     }
     srt[cnt[r]].pb(r);
}

int lca(int u, int v){
     if(h[u] < h[v]) swap(u, v);
     per(i,lg-1,0) if(h[par[u][i]] >= h[v]) u = par[u][i];
     if(u == v) return u;
     per(i,lg-1,0) if(par[u][i] - par[v][i]) u = par[u][i], v = par[v][i];
     return par[u][0];
}

int dist(int u, int v){
     return h[u] + h[v] - 2*h[lca(u, v)];
}

int getCen(int r, int p, int tot){
     for(int c: adj[r]) if(c - p && cnt[c] + cnt[c] > tot) return getCen(c, r, tot);
     return r;
}

int main(){ IOS();
     int n; cin >> n;
     rep(i,1,n){
          int u, v; cin >> u >> v; u--, v--;
          adj[u].pb(v), adj[v].pb(u);
     }
     dfs(0, -1);
     int r = getCen(0, -1, n);
     dfs2(r, r);
     vector<int> ans(n + 1, 1);
     int u = r, v = r, diam = 0;
     for(int k = n>>1; k > 0; k--){
          for(int x: srt[k]){
               int d1 = dist(x, u), d2 = dist(x, v);
               if(d1 > diam){
                    diam = d1, v = x;
               } else if(d2 > diam){
                    diam = d2, u = x;
               }
          }
          ans[k<<1] = diam + 1;
     }
     rep(i,1,n+1) cout << ans[i] << '\n';
     return 0;
}

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