Submission #675337

#	Time	Username	Problem	Language	Result	Execution time	Memory
675337		SanguineChameleon	Cheerleaders (info1cup20_cheerleaders)	C++17	100 / 100	393 ms	2992 KiB

cheerleaders

// 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 kt = 17;
const int ms = 1 << kt;
int a[ms];
pair<int, int> p[ms];
pair<int, int> q[ms];
long long cv[kt][2];
int cc[2];

int n;

int shift(int x, int k) {
	return (x >> k) | ((x & ((1 << k) - 1)) << (n - k));
}

void solve(int lt, int rt, int k) {
	if (k == -1) {
		return;
	}
	int mt = (lt + rt) >> 1;
	solve(lt, mt, k - 1);
	solve(mt + 1, rt, k - 1);
	for (int i = lt; i <= mt; i++) {
		p[i].second = 0;
	}
	for (int i = mt + 1; i <= rt; i++) {
		p[i].second = 1;
	}
	merge(p + lt, p + mt + 1, p + mt + 1, p + rt + 1, q + lt);
	copy(q + lt, q + rt + 1, p + lt);
	cc[0] = 0;
	cc[1] = 0;
	for (int i = lt; i <= rt; i++) {
		cv[k][p[i].second] += cc[p[i].second ^ 1];
		cc[p[i].second]++;
	}
}

void just_do_it() {
	cin >> n;
	for (int i = 0; i < (1 << n); i++) {
		cin >> a[i];
	}
	if (n == 0) {
		cout << 0;
		return;
	}
	long long res = (long long)1e18 + 20;
	string s = "";
	for (int k = 0; k < n; k++) {
		for (int i = 0; i < (1 << n); i++) {
			p[shift(i, k)] = {a[i], -1};
		}
		for (int i = 0; i < n; i++) {
			cv[i][0] = 0;
			cv[i][1] = 0;
		}
		solve(0, (1 << n) - 1, n - 1);
		long long cr = 0;
		int h = 0;
		for (int i = 0; i < n; i++) {
			if (cv[i][0] < cv[i][1]) {
				cr += cv[i][0];
			}
			else {
				h |= (1 << i);
				cr += cv[i][1];
			}
		}
		h = shift(h, n - k);
		if (cr < res) {
			res = cr;
			s = "";
			for (int i = 0; i < n; i++) {
				s += "2";
				if ((h >> i) & 1) {
					s += "1";
				}
			}
			for (int i = 0; i < k; i++) {
				s += "2";
			}
		}
	}
	cout << res << '\n';
	cout << s;
}

// END MAIN CODE

Compilation message (stderr)

cheerleaders.cpp: In function 'void file_io(std::string, std::string)':
cheerleaders.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);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
cheerleaders.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: 16 / 16
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 21 / 21
• Subtask 5: 28 / 28