Submission #710711

#	Time	Username	Problem	Language	Result	Execution time	Memory
710711		noedit	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	89 ms	24876 KiB

catinatree

#include <bits/stdc++.h>
#include <quadmath.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//#define sz(x) (int)x.size()
//#define sqr(x) x*x
//#pragma GCC optimize("-O3")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,sse4.1,sse4.2,popcnt,abm,mmx,avx,avx2,tune=native")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("no-stack-protector")
//#pragma GCC optimize("fast-math")
using namespace std;
//using namespace __gnu_pbds;
//
//#define int long long
////#define ld long double
//template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;

vector<vector<int> > g;

int d;

pair<int, int> dfs(int v, int p)
{
    vector<pair<int, int> > cur;
    cur.push_back({0, 1});
    int total = 1;
    for (auto& u : g[v])
    {
        if (u != p)
        {
            auto[res, mn_dep] = dfs(u, v);
            total += res;
            cur.push_back({mn_dep, res});
        }
    }
    sort(cur.rbegin(), cur.rend());
    while (cur.size() > 1 && cur[cur.size() - 1].first + cur[cur.size() - 2].first < d)
    {
        total--;
        cur.pop_back();
    }
//    if (cur[0].first == d)
//        return {total + 1, 1};
    return {total, cur.back().first + 1};
}

void solve()
{
    int n;
    cin >> n >> d;
    g.resize(n);
    for (int i = 1; i < n; i++)
    {
        int p;
        cin >> p;
        g[p].push_back(i);
    }
    auto [ans, mn] = dfs(0, 0);
    cout << ans;
}
//
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t;
    t = 1;
    //cin >> t;
    while (t--)
    {
        solve();
    }
    cerr << endl << fixed << setprecision(3) << "Time execution: " << (double)clock() / CLOCKS_PER_SEC << endl;
    return 0;
}
//
//
/*
17 13
1 3 1 2 1 3 1 2 1 1 2 1 2 1 2 1 3
3 1 2 3 3 2 1 2 1 3 2 2 1
*/
/*
6 9
3 2 1 6 7 4
3 2 6 10 8 9 7 1 4
*/
/*
9 8
2 1 4 6 7 8 9 10 11
8 9 10 11 1 4 6 7
*/

• Subtask 1: 11 / 11
• Subtask 2: 40 / 40
• Subtask 3: 49 / 49