Submission #1263621

#	Time	Username	Problem	Language	Result	Execution time	Memory
1263621		NikoBaotic	Monochrome Points (JOI20_monochrome)	C++20	4 / 100	2093 ms	328 KiB

monochrome

#include "bits/stdc++.h"

using namespace std;

typedef long long ll;
typedef pair<ll, ll> pii;

#define all(x) x.begin(), x.end()
#define sz(x) ((int) ((x).size()))
#define pb push_back
#define F first
#define S second
#define FIO ios_base::sync_with_stdio(false); cin.tie(0)

const int N = 200;

int n;
string s;
int st[N];
int pozB[N];
int pozC[N];
vector<int> v;

int run() {
	int ans = 0;

	for (int i = 0; i < n * 2; i++) {
		if (i < v[i]) continue;

		for (int j = 0; j < n * 2; j++) {
			st[j] = 0;
		}

		int cur = (v[i] + 1) % sz(v);

		vector<int> k;

		while (cur != i) {
			k.pb(cur);
			st[cur] = 1;

			cur++;
			cur %= sz(v);
		}

		for (int x : k) {
			if (st[v[x]] == 0) {
				ans++;
			}
		}
	}

	return ans;
}

int main() {
	FIO;
	
	cin >> n;
	cin >> s;

	int cntB = 0;
	int cntC = 0;

	for (int i = 0; i < n * 2; i++) {
		if (s[i] == 'W') { pozB[cntB] = i; cntB++; }
		if (s[i] == 'B') { pozC[cntC] = i; cntC++; }
	}

	vector<int> p;

	for (int i = 0; i < n; i++) {
		p.pb(i);
	}

	int ans = 0;

	do {
		v.clear();
		v.resize(n * 2);

		for (int i = 0; i < n; i++) {
			int x = pozB[i];
			int y = pozC[p[i]];

			v[x] = y;
			v[y] = x;
		}

		ans = max(ans, run());
	} while (next_permutation(all(p)));

	cout << ans / 2 << endl;

	return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 0 / 21
• Subtask 3: 0 / 10
• Subtask 4: 0 / 65