제출 #681990

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
681990		SanguineChameleon	Event Hopping (BOI22_events)	C++17	0 / 100	139 ms	14896 KiB

events

// 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);
}

long double rand_real(long double rmin, long double rmax) {
	uniform_real_distribution<long double> 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 = 1e5 + 20;
const int st = 20;
int nxt[ms][st];
int lt[ms];
int rt[ms];

void just_do_it() {
	int n, q;
	cin >> n >> q;
	vector<pair<int, int>> p;
	for (int i = 1; i <= n; i++) {
		cin >> lt[i] >> rt[i];
		p.push_back({lt[i], -i});
		p.push_back({rt[i], i});
	}
	sort(p.begin(), p.end());
	set<pair<int, int>> s;
	for (auto x: p) {
		if (x.second < 0) {
			s.insert({rt[-x.second], -x.second});
		}
		else {
			nxt[x.second][0] = s.rbegin()->second;
			s.erase({rt[x.second], x.second});
		}
	}
	for (int k = 1; k < st; k++) {
		for (int i = 1; i <= n; i++) {
			nxt[i][k] = nxt[nxt[i][k - 1]][k - 1];
		}
	}

	for (int i = 0; i < q; i++) {
		int u, v;
		cin >> u >> v;
		if (u == v) {
			cout << 0 << '\n';
			continue;
		}
		if (rt[u] > rt[v]) {
			cout << "impossible" << '\n';
			continue;
		}
		int res = 0;
		for (int k = st - 1; k >= 0; k--) {
			if (rt[nxt[u][k]] < rt[v]) {
				u = nxt[u][k];
				res |= 1 << k;
			}
		}
		if (nxt[u][0] != v) {
			cout << "impossible" << '\n';
		}
		else {
			res++;
			cout << res << '\n';
		}
	}
}

// END MAIN CODE

컴파일 시 표준 에러 (stderr) 메시지

events.cpp: In function 'void file_io(std::string, std::string)':
events.cpp:30:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |   freopen(fi.c_str(), "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
events.cpp:33:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |   freopen(fo.c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30