제출 #630813

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
630813		SanguineChameleon	Cat in a tree (BOI17_catinatree)	C++14	51 / 100	257 ms	54364 KiB

catinatree

// BEGIN BOILERPLATE CODE

#include <bits/stdc++.h>
using namespace std;

#ifdef KAMIRULEZ
	const bool kami_loc = true;
	const long long kami_seed = 69420;
#else
	const bool kami_loc = false;
	const long long kami_seed = chrono::steady_clock::now().time_since_epoch().count();
#endif

const string kami_fi = "kamirulez.inp";
const string kami_fo = "kamirulez.out";
mt19937_64 kami_gen(kami_seed);

long long rand_range(long long rmin, long long rmax) {
	uniform_int_distribution<long long> rdist(rmin, rmax);
	return rdist(kami_gen);
}

void file_io(string fi, string fo) {
	if (fi != "" && (!kami_loc || fi == kami_fi)) {
		freopen(fi.c_str(), "r", stdin);
	}
	if (fo != "" && (!kami_loc || fo == kami_fo)) {
		freopen(fo.c_str(), "w", stdout);
	}
}

void set_up() {
	if (kami_loc) {
		file_io(kami_fi, kami_fo);
	}
	ios_base::sync_with_stdio(0);
	cin.tie(0);
}

void just_do_it();

void just_exec_it() {
	if (kami_loc) {
		auto pstart = chrono::steady_clock::now();
		just_do_it();
		auto pend = chrono::steady_clock::now();
		long long ptime = chrono::duration_cast<chrono::milliseconds>(pend - pstart).count();
		string bar(50, '=');
		cout << '\n' << bar << '\n';
		cout << "Time: " << ptime << " ms" << '\n';
	}
	else {
		just_do_it();
	}
}

int main() {
	set_up();
	just_exec_it();
	return 0;
}

// END BOILERPLATE CODE

// BEGIN MAIN CODE

const int ms = 2e5 + 20;
const int st = 20;
vector<int> ch[ms];
vector<int> adj[ms];
int de[ms];
int a[ms];
int lg[ms * 2];
int h[ms * 2][st];
int pt[ms];
bool f[ms];
int tz;

void dfs(int u) {
	tz++;
	pt[u] = tz;
	h[tz][0] = de[u];
	for (auto v: ch[u]) {
		de[v] = de[u] + 1;
		dfs(v);
		tz++;
		h[tz][0] = de[u];
	}
}

bool cmp(int x, int y) {
	return de[x] > de[y];
}

int dist(int u, int v) {
	int lt = pt[u];
	int rt = pt[v];
	if (lt > rt) {
		swap(lt, rt);
	}
	int k = lg[rt - lt + 1];
	return de[u] + de[v] - 2 * min(h[lt][k], h[rt - (1 << k) + 1][k]);
}

void just_do_it() {
	lg[1] = 0;
	for (int i = 2; i < ms * 2; i++) {
		lg[i] = lg[i / 2] + 1;
	}
	int n, d;
	cin >> n >> d;
	for (int i = 2; i <= n; i++) {
		int u;
		cin >> u;
		u++;
		ch[u].push_back(i);
		adj[u].push_back(i);
		adj[i].push_back(u);
	}
	dfs(1);
	for (int k = 1; k < st; k++) {
		for (int i = 1; i + (1 << k) - 1 <= n * 2; i++) {
			h[i][k] = min(h[i][k - 1], h[i + (1 << (k - 1))][k - 1]);
		}
	}
	iota(a + 1, a + n + 1, 1);
	sort(a + 1, a + n + 1, cmp);
	deque<int> p;
	int res = 0;
	for (int i = 1; i <= n; i++) {
		int u = a[i];
		if (f[u]) {
			continue;
		}
		bool ok = true;
		for (auto x: p) {
			if (dist(x, u) < d) {
				ok = false;
				break;
			} 
		}
		if (!ok) {
			continue;
		}
		p.push_back(u);
		res++;
		if (p.size() % 400 == 0) {
			deque<int> z;
			for (auto x: p) {
				f[x] = true;
				z.push_back(0);
			}
			while (!p.empty()) {
				int u = p.front();
				int cd = z.front();
				p.pop_front();
				z.pop_front();
				if (cd == d - 1) {
					continue;
				}
				for (auto v: adj[u]) {
					if (!f[v]) {
						f[v] = true;
						p.push_back(v);
						z.push_back(cd + 1);
					}
				}
			}
		}
	}
	cout << res;
}

// END MAIN CODE

컴파일 시 표준 에러 (stderr) 메시지

catinatree.cpp: In function 'void file_io(std::string, std::string)':
catinatree.cpp:25:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |   freopen(fi.c_str(), "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
catinatree.cpp:28:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |   freopen(fo.c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 40 / 40
• Subtask 3: 0 / 49