oj.uz

Submission #756030

# Submission time Handle Problem Language Result Execution time Memory
756030 2023-06-10T22:43:29 Z badont Cat in a tree (BOI17_catinatree) C++17
11 / 100
 29 ms 45732 KB 
#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <cassert>
#include <array>
#include <numeric>
#include <set>
#include <queue>
using namespace std;
using ll = long long;
#define pb push_back
template<typename T, typename = void> struct is_iterable : false_type {};
template<typename T> struct is_iterable<T, void_t<decltype(begin(declval<T>())),decltype(end(declval<T>()))>> : true_type {};
template<typename T> typename enable_if<is_iterable<T>::value&&!is_same<T, string>::value,ostream&>::type operator<<(ostream &cout, T const &v);
template<typename A, typename B> ostream& operator<<(ostream &cout, pair<A, B> const &p) { return cout << "(" << p.f << ", " << p.s << ")"; }
template<typename T> typename enable_if<is_iterable<T>::value&&!is_same<T, string>::value,ostream&>::type operator<<(ostream &cout, T const &v) {
	cout << "["; 
	for (auto it = v.begin(); it != v.end();) {
		cout << *it;
		if (++it != v.end()) cout << ", ";
	}
	return cout << "]";
}

void dbg_out() { cout << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cout << ' ' << H; dbg_out(T...); }

#ifdef LOCAL
#define debug(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define debug(...) "zzz"
#endif

#define all(x) x.begin(),x.end()
#define F0R(i,n) for (int i = 0; i < n; i++)

//benq
constexpr ll INF = 1e9;
struct Lazy {
    ll app, x;
    Lazy(ll a, ll b) : app(a), x(b) {}
    Lazy() : app(INF), x(-INF) {}
    Lazy& operator+=(const Lazy& o) {
        this->app = min(this->app, o.app);
        this->x = max(this->x, o.x);
        return *this;
    }
};
struct Info {
    ll max_depth, min_active;
    Info() : max_depth(-INF), min_active(INF) {}
    Info(ll md, ll ma) : max_depth(md), min_active(ma) {}
    friend Info operator+(const Info& a, const Info& b) {
        Info ret;
        ll val_1 = a.min_active - 2LL * a.max_depth;
        ll val_2 = b.min_active - 2LL * b.max_depth;
        if (val_1 < val_2) return a;
        else return b;
    }
    Info& operator+=(const Lazy& o) {
        this->max_depth = max(this->max_depth, o.x);
        this->min_active = min(this->min_active, o.app);
        return *this;
    }
};


template<class T, int SZ, class Lazy> struct LazySeg { 
	//zero indexed
	static_assert(__builtin_popcount(SZ) == 1); // SZ must be power of 2
	const T ID{}; T cmb(const T& a, const T& b) { return a+b; }
	T seg[2*SZ];
    Lazy lazy[2*SZ]; 
	LazySeg() { F0R(i,2*SZ) seg[i] = {}, lazy[i] = {}; }
	void push(int ind, int L, int R) { /// modify values for current node
		seg[ind] += lazy[ind]; // dependent on operation
		if (L != R) F0R(i,2) lazy[2*ind+i] += lazy[ind]; /// prop to children
		lazy[ind] = {}; 
	} // recalc values for current node
	void pull(int ind){seg[ind]=cmb(seg[2*ind],seg[2*ind+1]);}
	void build() { for (int i = SZ - 1; i >= 1; --i) pull(i); }
	void upd(int lo,int hi,const Lazy& inc,int ind=1,int L=0, int R=SZ-1) {
		push(ind,L,R); if (hi < L || R < lo) return;
		if (lo <= L && R <= hi) { 
			lazy[ind] += inc; push(ind,L,R); return; }
		int M = (L+R)/2; upd(lo,hi,inc,2*ind,L,M); 
		upd(lo,hi,inc,2*ind+1,M+1,R); pull(ind);
	}
	T query(int lo, int hi, int ind=1, int L=0, int R=SZ-1) {
		push(ind,L,R); if (lo > R || L > hi) return ID;
		if (lo <= L && R <= hi) return seg[ind];
		int M = (L+R)/2; return cmb(query(lo,hi,2*ind,L,M),
			query(lo,hi,2*ind+1,M+1,R));
	}
};

template<int SZ, bool VALS_IN_EDGES> struct HLD { 
	int N; vector<int> adj[SZ];
	int par[SZ], root[SZ], depth[SZ], sz[SZ], ti;
	int pos[SZ]; vector<int> rpos; // rpos not used but could be useful
	void ae(int x, int y) { adj[x].pb(y), adj[y].pb(x); }
	void dfsSz(int x) { 
		sz[x] = 1; 
		for (auto& y : adj[x]) {
			par[y] = x; depth[y] = depth[x]+1;
			adj[y].erase(find(all(adj[y]),x)); /// remove parent from adj list
			dfsSz(y); sz[x] += sz[y];
			if (sz[y] > sz[adj[x][0]]) swap(y,adj[x][0]);
		}
	}
	void dfsHld(int x) {
		pos[x] = ti++; rpos.pb(x);
		for (auto& y : adj[x]) {
			root[y] = (y == adj[x][0] ? root[x] : y);
			dfsHld(y); }
	}
	void init(int _N, int R = 0) { N = _N; 
		par[R] = depth[R] = ti = 0; dfsSz(R); 
		root[R] = R; dfsHld(R); 
	}
	int lca(int x, int y) {
		for (; root[x] != root[y]; y = par[root[y]])
			if (depth[root[x]] > depth[root[y]]) swap(x,y);
		return depth[x] < depth[y] ? x : y;
	}
	/// int dist(int x, int y) { // # edges on path
	/// 	return depth[x]+depth[y]-2*depth[lca(x,y)]; }
	LazySeg<Info,SZ,Lazy> tree; // segtree for sum
	template <class BinaryOp>
	void processPath(int x, int y, BinaryOp op) {
		for (; root[x] != root[y]; y = par[root[y]]) {
			if (depth[root[x]] > depth[root[y]]) swap(x,y);
			op(pos[root[y]],pos[y]); }
		if (depth[x] > depth[y]) swap(x,y);
		op(pos[x]+VALS_IN_EDGES,pos[y]); 
	}
	void modifyPath(int x, int y, const Lazy& v) { 
		processPath(x,y,[this,&v](int l, int r) { 
			tree.upd(l,r,v); }); }
	Info queryPath(int x, int y) { 
		Info res = {}; processPath(x,y,[this,&res](int l, int r) { 
			res = res + tree.query(l,r); });
		return res; }
};

HLD<1<<19, false> hld;

void solve() {
    ll n, d;
    cin >> n >> d;

    vector e(n, vector<ll>());
    for (int i = 0; i < n - 1; i++) {
        ll x; cin >> x;
        hld.ae(x, i + 1);
        e[x].pb(i + 1);
        e[i + 1].pb(x);
    }
    hld.init(n, 0);
    vector<ll> depth(n);
    auto dfs = [&](auto& dfs, ll g, ll p, ll d) -> void {
        depth[g] = d;
        hld.modifyPath(g, g, Lazy(INF, depth[g]));
        for (auto u : e[g]) if (u != p) {
            dfs(dfs, u, g, d + 1);
        }
    };
    dfs(dfs, 0, -1, 0);
    vector<ll> p(n);
    iota(all(p), 0);
    sort(all(p), [&](ll x, ll y) {
        return depth[x] > depth[y];
    });

    vector<ll> ans;
    for (auto u : p) {
        Info to_root = hld.queryPath(0, u);
        ll root_val = to_root.min_active - 2LL * to_root.max_depth;
        if (root_val + depth[u] >= d) {
            ans.pb(u);
            // activate u
            hld.modifyPath(0, u, Lazy(depth[u], -INF));
        }
    }

    sort(all(ans));
    cout << ans.size() << '\n';
    /*
    for (const auto& u : ans)
        cout << u + 1 << ' ';
    cout << '\n';
    */
}

int main() {
    cin.tie(0)->sync_with_stdio(false);
    solve();
    return 0;
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 45396 KB Output is correct
2 Correct 22 ms 45396 KB Output is correct
3 Correct 21 ms 45436 KB Output is correct
4 Correct 22 ms 45504 KB Output is correct
5 Correct 21 ms 45396 KB Output is correct
6 Correct 24 ms 45464 KB Output is correct
7 Correct 23 ms 45504 KB Output is correct
8 Correct 22 ms 45480 KB Output is correct
9 Correct 23 ms 45460 KB Output is correct
10 Correct 27 ms 45388 KB Output is correct
11 Correct 29 ms 45396 KB Output is correct
12 Correct 25 ms 45396 KB Output is correct
13 Correct 27 ms 45388 KB Output is correct
14 Correct 23 ms 45392 KB Output is correct
15 Correct 23 ms 45396 KB Output is correct
16 Correct 23 ms 45460 KB Output is correct
17 Correct 23 ms 45456 KB Output is correct
18 Correct 22 ms 45416 KB Output is correct
19 Correct 25 ms 45396 KB Output is correct
20 Correct 24 ms 45396 KB Output is correct

Subtask #2
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 45396 KB Output is correct
2 Correct 22 ms 45396 KB Output is correct
3 Correct 21 ms 45436 KB Output is correct
4 Correct 22 ms 45504 KB Output is correct
5 Correct 21 ms 45396 KB Output is correct
6 Correct 24 ms 45464 KB Output is correct
7 Correct 23 ms 45504 KB Output is correct
8 Correct 22 ms 45480 KB Output is correct
9 Correct 23 ms 45460 KB Output is correct
10 Correct 27 ms 45388 KB Output is correct
11 Correct 29 ms 45396 KB Output is correct
12 Correct 25 ms 45396 KB Output is correct
13 Correct 27 ms 45388 KB Output is correct
14 Correct 23 ms 45392 KB Output is correct
15 Correct 23 ms 45396 KB Output is correct
16 Correct 23 ms 45460 KB Output is correct
17 Correct 23 ms 45456 KB Output is correct
18 Correct 22 ms 45416 KB Output is correct
19 Correct 25 ms 45396 KB Output is correct
20 Correct 24 ms 45396 KB Output is correct
21 Correct 25 ms 45732 KB Output is correct
22 Correct 25 ms 45524 KB Output is correct
23 Incorrect 24 ms 45436 KB Output isn't correct
24 Halted 0 ms 0 KB -

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 45396 KB Output is correct
2 Correct 22 ms 45396 KB Output is correct
3 Correct 21 ms 45436 KB Output is correct
4 Correct 22 ms 45504 KB Output is correct
5 Correct 21 ms 45396 KB Output is correct
6 Correct 24 ms 45464 KB Output is correct
7 Correct 23 ms 45504 KB Output is correct
8 Correct 22 ms 45480 KB Output is correct
9 Correct 23 ms 45460 KB Output is correct
10 Correct 27 ms 45388 KB Output is correct
11 Correct 29 ms 45396 KB Output is correct
12 Correct 25 ms 45396 KB Output is correct
13 Correct 27 ms 45388 KB Output is correct
14 Correct 23 ms 45392 KB Output is correct
15 Correct 23 ms 45396 KB Output is correct
16 Correct 23 ms 45460 KB Output is correct
17 Correct 23 ms 45456 KB Output is correct
18 Correct 22 ms 45416 KB Output is correct
19 Correct 25 ms 45396 KB Output is correct
20 Correct 24 ms 45396 KB Output is correct
21 Correct 25 ms 45732 KB Output is correct
22 Correct 25 ms 45524 KB Output is correct
23 Incorrect 24 ms 45436 KB Output isn't correct
24 Halted 0 ms 0 KB -