Submission #387643

#	Time	Username	Problem	Language	Result	Execution time	Memory
387643		casperwang	Cheerleaders (info1cup20_cheerleaders)	C++14	26 / 100	2076 ms	1356 KiB

cheerleaders

#include <bits/stdc++.h>
#define pb emplace_back
#define All(x) x.begin(), x.end()
#define pii pair<int,int>
#define ff first
#define ss second
using namespace std;
#define debug(args...) kout("[ " + string(#args) + " ]", args)
void kout() { cerr << endl; }
template <class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ',kout(b...); }
template <class T> void pary(T L, T R) { while (L != R) cerr << *L << " \n"[++L==R]; }

const int MAXN = 17;
int N;
int ans;
pii op;
string ops;
vector <int> a, c, fin;
int val[MAXN+1];

inline int lb(int a) {
	return a &- a;
}

void init() {
	a.resize(1<<N);
	c.resize(1<<N);
}

void build() {
}

int cnt() {
	int s = 0;
	for (int i = 0; i < (1<<N); i++) {
		for (int j = i+1; j < (1<<N); j++) {
			s += c[i] > c[j];
		}
	}
	return s;
}

void test(string str, vector <int> c) {
	for (int i = 0; i < str.size(); i++) {
		if (str[i] == '2') {
			for (int j = 0; j < (1<<N); j++) {
				c[j] = (1<<(N-1)) * (c[j] & 1) + c[j] / 2;
			}
		} else if (str[i] == '1') {
			for (int j = 0; j < (1<<N); j++) {
				c[j] ^= (1<<(N-1));
			}
		}
	}
	pary(All(c));
}

string solve(pii op) {
	string str;
	debug(op.ff, op.ss);
	for (int i = 0; i < op.ff; i++)
		str += '2';
	for (int i = 0; i < N; i++) {
		str += '2';
		if ((1<<i) & op.ss) {
			str += '1';
		}
	}
	return str;
}

signed main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	cin >> N;
	init();
	for (int i = 0; i < (1<<N); i++)
		cin >> a[i], c[a[i]] = i;
	ans = cnt();
	a = c;
	for (int j = 0; j < N; j++) {
		// build();
		int x = 0;
		vector <int> tmp = c;
		for (int i = 1; i < (1<<N); i++) {
			for (int k = 0; k < (1<<N); k++) {
				c[k] ^= lb(i);
			}
			x ^= lb(i);
			int C = cnt();
			if (C < ans) {
				ans = C, op = pii(j, x);
				fin = c;
			}
		}
		c = tmp;
		for (int i = 0; i < (1<<N); i++) {
			c[i] = (1<<(N-1)) * (c[i] & 1) + c[i] / 2;
		}
	}
	cout << ans << '\n';
	cout << solve(op) << '\n';
	return 0;
}

Compilation message (stderr)

cheerleaders.cpp: In function 'void test(std::string, std::vector<int>)':
cheerleaders.cpp:44:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |  for (int i = 0; i < str.size(); i++) {
      |                  ~~^~~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 10 / 10
• Subtask 3: 0 / 25
• Subtask 4: 0 / 21
• Subtask 5: 0 / 28