Submission #869468

#	Time	Username	Problem	Language	Result	Execution time	Memory
869468		wakandaaa	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	48 ms	21844 KiB

catinatree

#include <bits/stdc++.h>

using namespace std;

#define file ""

#define mp make_pair
#define fi first
#define se second
#define all(x) x.begin(), x.end()

#define getbit(x, i) (((x) >> (i)) & 1)
#define bit(x) (1LL << (x))
#define popcount __builtin_popcountll

mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r) {
    return l + rd() % (r - l + 1);
}

const int N = 2e5 + 5;
const int mod = (int)1e9 + 7; // 998244353;
const int lg = 25; // lg + 1
const int oo = 1e9;
const long long ooo = 1e18;

template<class X, class Y> bool mini(X &a, Y b) {
    return a > b ? (a = b, true) : false;
}
template<class X, class Y> bool maxi(X &a, Y b) {
    return a < b ? (a = b, true) : false;
}
void add(int &a, int b) {
    a += b;
    if (a >= mod) a -= mod;
    if (a < 0) a += mod;
}

int n, d;
vector<int> adj[N];

namespace greedy {

int h[N], f[N];

void dfs(int u, int p) {
    h[u] = oo;
    for (int v : adj[u]) if (v != p) {
        dfs(v, u);
        if (h[u] + h[v] + 1 >= d) {
            f[u] += f[v];
            mini(h[u], h[v] + 1);
        }
        else {
            f[u] += f[v] - 1;
            maxi(h[u], h[v] + 1);
        }
    }
    if (h[u] >= d) {
        f[u] += 1;
        h[u] = 0;
    }
}

void solve() {
    dfs(1, 0);

    cout << f[1];
}

}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);

    cin >> n >> d;
    for (int i = 2; i <= n; ++i) {
        int p;
        cin >> p;
        ++p;
        adj[i].push_back(p);
        adj[p].push_back(i);
    }

    greedy::solve();

    return 0;
}

/*

*/

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