Submission #683856

#	Time	Username	Problem	Language	Result	Execution time	Memory
683856		abc864197532	Monochrome Points (JOI20_monochrome)	C++17	4 / 100	1 ms	340 KiB

monochrome

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define pii pair<int,int>
#define all(x) x.begin(), x.end()

int main() {
	ios::sync_with_stdio(false), cin.tie(0);
	int n;
	string s;
	cin >> n >> s;
	vector <int> W, B;
	for (int i = 0; i < n; ++i) {
		if (s[i] == s[i + n]) {
			(s[i] == 'W' ? W : B).pb(i);
		}
	}
	int m = W.size();
	vector <vector <ll>> dp(m + 1, vector <ll> (m + 1, 1ll << 60));
	for (int i = 0; i <= m; ++i) {
		dp[i][i] = 0;
	}
	for (int len = 1; len <= m; ++len) {
		for (int i = 0; i + len <= m; ++i) {
			int j = i + len;
			{
				int cost = abs(W[len - 1] - B[i]);
				dp[i][j] = min(dp[i][j], dp[i + 1][j] + min(cost, n - cost));
			}
			{
				int cost = abs(W[len - 1] - B[j - 1]);
				dp[i][j] = min(dp[i][j], dp[i][j - 1] + min(cost, n - cost));
			}
		}
	}
	cout << 1ll * n * (n - 1) / 2 - dp[0][m] << '\n';
}

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