Submission #591175

#	Time	Username	Problem	Language	Result	Execution time	Memory
591175		tutis	Boarding Passes (BOI22_passes)	C++17	5 / 100	3 ms	2832 KiB

passes

/*input
ABABABAB
*/
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
ll dp[1 << 15];
int main()
{
	ios_base::sync_with_stdio(false);
	string s;
	cin >> s;
	for (int i = 0; i < (1 << 15); i++)
		dp[i] = 1e18;
	dp[0] = 0;
	vector<int>p[15];
	for (int i = 0; i < (int)s.size(); i++)
		p[s[i] - 'A'].push_back(i);
	int G = 15;
	while (p[G - 1].empty())
		G--;
	for (int msk = 0; msk < (1 << G); msk++)
	{
		for (int v = 0; v < G; v++)
		{
			if ((msk & (1 << v)) == 0)
			{
				int msk1 = msk ^ (1 << v);
				ll L[p[v].size() + 2];
				ll R[p[v].size() + 2];
				for (ll i = 0; i <= (int)p[v].size(); i++)
				{
					L[i] = 0;
					R[i] = 0;
				}
				for (int j = 0; j < (int)s.size(); j++)
				{
					if (((1 << (s[j] - 'A'))&msk) != 0)
					{
						auto it = lower_bound(p[v].begin(), p[v].end(), j);
						L[(it - p[v].begin())] += 4;
						R[(p[v].end() - it) + 1] += 4;
						//cout << ";" << (char)('A' + v) << " " << (it - p[v].begin()) << " " << (p[v].end() - it) + 1 << endl;
					}
				}
				for (ll i = 1; i <= (int)p[v].size(); i++)
					L[i] += L[i - 1];
				for (ll i = 1; i <= (int)p[v].size(); i++)
				{
					R[i] += R[i - 1];
					//cout << (char)('A' + v) << " " << i << " " << " " << L[i] / 4 << " " << R[i] / 4 << endl;
				}
				for (ll i = 1; i <= (int)p[v].size(); i++)
					L[i] += i * (i - 1);

				for (ll i = 1; i <= (int)p[v].size(); i++)
					R[i] += i * (i - 1);

				ll best = 1e18;
				for (int l = 0; l <= (int)p[v].size(); l++)
				{
					best = min(best, L[l] + R[(int)p[v].size() - l]);
				}
				dp[msk1] = min(dp[msk1], dp[msk] + best);
			}
		}
	}
	ll ret = dp[(1 << G) - 1];
	cout << ret / 4;
	if (ret % 4 == 2)
	{
		cout << ".5";
	}
	else if (ret % 4 != 0)
	{
		cout << "." << 25 * (ret % 4);
	}
	cout << "\n";
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 25
• Subtask 3: 0 / 30
• Subtask 4: 0 / 40