Submission #681983

#	Time	Username	Problem	Language	Result	Execution time	Memory
681983		SanguineChameleon	Event Hopping (BOI22_events)	C++17	10 / 100	1586 ms	3148 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;
int lt[ms];
int rt[ms];
int n;

void query() {
	int u, v;
	cin >> u >> v;
	if (u == v) {
		cout << 0 << '\n';
		return;
	}
	int res = 0;
	while (true) {
		res++;
		int best = u;
		for (int i = 1; i <= n; i++) {
			if (lt[i] <= rt[u] && rt[u] <= rt[i] && rt[i] <= rt[v]) {
				if (i == v) {
					cout << res << '\n';
					return;
				}
				if (rt[i] > rt[best]) {
					best = i;
				}
			}
		}
		if (best == u) {
			cout << "impossible" << '\n';
			return;
		}
		u = best;
	}
}

void just_do_it() {
	int q;
	cin >> n >> q;
	for (int i = 1; i <= n; i++) {
		cin >> lt[i] >> rt[i];
	}
	for (int i = 0; i < q; i++) {
		query();
	}
}

// END MAIN CODE

Compilation message (stderr)

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