Submission #543346

#	Time	Username	Problem	Language	Result	Execution time	Memory
543346		wiwiho	Meetings 2 (JOI21_meetings2)	C++14	100 / 100	438 ms	46892 KiB

meetings2

#include <bits/stdc++.h>
#include <bits/extc++.h>

#define StarBurstStream ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define lsort(a) sort(iter(a))
#define gsort(a) sort(riter(a))
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define pf(a) push_front(a)
#define ef(a) emplace_front(a)
#define pob pop_back()
#define pof pop_front()
#define mp(a, b) make_pair(a, b)
#define F first
#define S second
#define mt make_tuple
#define gt(t, i) get<i>(t)
#define tomax(a, b) ((a) = max((a), (b)))
#define tomin(a, b) ((a) = min((a), (b)))
#define topos(a) ((a) = (((a) % MOD + MOD) % MOD))
#define uni(a) a.resize(unique(iter(a)) - a.begin())
#define printv(a, b) {bool pvaspace=false; \
for(auto pva : a){ \
    if(pvaspace) b << " "; pvaspace=true;\
    b << pva;\
}\
b << "\n";}

using namespace std;
using namespace __gnu_pbds;

#define orz
#ifdef orz
#define print(a...)cerr<<"Line "<<__LINE__<<":",kout("[" + string(#a) + "] = ", a)
void kout() { cerr << endl; }
template<class T1, class ... T2> void kout(T1 a, T2 ... e) { cerr << a << " ", kout(e...); }
#else
#define print(a..)
void kout() {}
template<class T1, class ... T2> void kout(T1 a, T2 ... e) {}
#endif

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;
using tiii = tuple<int, int, int>;

const ll MOD = 1000000007;
const ll MAX = 2147483647;

template<typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> p){
    return o << '(' << p.F << ',' << p.S << ')';
}

ll ifloor(ll a, ll b){
    if(b < 0) a *= -1, b *= -1;
    if(a < 0) return (a - b + 1) / b;
    else return a / b;
}

ll iceil(ll a, ll b){
    if(b < 0) a *= -1, b *= -1;
    if(a > 0) return (a + b - 1) / b;
    else return a / b;
}

int main(){
    StarBurstStream

    int n;
    cin >> n;
    vector<vector<int>> g(n + 1);

    for(int i = 0; i < n - 1; i++){
        int u, v;
        cin >> u >> v;
        g[u].eb(v);
        g[v].eb(u);
    }

    vector<int> sz(n + 1);
    int cen = -1;
    
    function<void(int, int)> dfs;
    dfs = [&](int now, int p){
        sz[now] = 1;
        int mx = 0;
        for(int i : g[now]){
            if(i == p) continue;
            dfs(i, now);
            sz[now] += sz[i];
            mx = max(mx, sz[i]);
        }
        mx = max(mx, n - sz[now]);
        if(mx <= n / 2) cen = now;
    };
    dfs(1, 1);

    vector<pii> all;
    vector<int> in(n + 1), out(n + 1), dpt(n + 1);
    const int SZ = 20;
    vector<vector<int>> anc(SZ, vector<int>(n + 1));
    int ts = 0;
    dfs = [&](int now, int p){
        dpt[now] = dpt[p] + 1;
        anc[0][now] = p;
        in[now] = ts++;
        sz[now] = 1;
        for(int i : g[now]){
            if(i == p) continue;
            dfs(i, now);
            sz[now] += sz[i];
        }
        all.eb(mp(sz[now], now));
        out[now] = ts++;
    };
    dfs(cen, cen);
    gsort(all);
    
    for(int i = 1; i < SZ; i++){
        for(int j = 1; j <= n; j++) anc[i][j] = anc[i - 1][anc[i - 1][j]];
    }

    auto isAnc = [&](int a, int b){
        return in[a] <= in[b] && out[a] >= out[b];
    };
    auto getlca = [&](int a, int b){
        if(isAnc(a, b)) return a;
        for(int i = SZ - 1; i >= 0; i--){
            if(!isAnc(anc[i][a], b)) a = anc[i][a];
        }
        return anc[0][a];
    };
    auto dis = [&](int a, int b){
        int lca = getlca(a, b);
        return dpt[a] + dpt[b] - 2 * dpt[lca];
    };
    //cerr << cen << "\n";
    //printv(all, cerr);

    int v1 = cen, v2 = cen;
    auto upd = [&](int v){
        //cerr << "upd " << v << "\n";
        if(dis(v1, v) > dis(v1, v2)) v2 = v;
        else if(dis(v, v2) > dis(v1, v2)) v1 = v;
    };

    int p = 0;
    vector<int> ans(n + 1);
    for(int i = n; i >= 1; i--){
        if(i % 2 == 1){
            ans[i] = 1;
            continue;
        }
        while(p < n && all[p].F >= i / 2){
            upd(all[p].S);
            p++;
        }
        //cerr << "ans " << i << "\n";
        ans[i] = dis(v1, v2) + 1;
    }
    for(int i = 1; i <= n; i++) cout << ans[i] << "\n";

    return 0;
}

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