Submission #1032530

#	Time	Username	Problem	Language	Result	Execution time	Memory
1032530		juicy	Growing Vegetable is Fun 3 (JOI19_ho_t3)	C++17	100 / 100	388 ms	782272 KiB

joi2019_ho_t3

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

const int N = 405;

int n;
string s;
int sf[3][N][N], dp[N][N][N][3];

int conv(char c) {
	return c == 'R' ? 0 : (c == 'G' ? 1 : 2);
}

int main() {
	ios::sync_with_stdio(false); cin.tie(nullptr);
	
	cin >> n >> s;
	array<int, 3> cnt{};
	array<vector<int>, 3> pos;
	for (int i = 0; i < n; ++i) {
		int c = conv(s[i]);
		++cnt[c];
		pos[c].push_back(i);
	}
	for (int i = 0; i < 3; ++i) {
		for (int j = 1; j <= n; ++j) {
			for (int k = cnt[i] - 1; k >= 0; --k) {
				sf[i][j][k] = sf[i][j][k + 1] + (pos[i][k] < j);
			}
		} 
	}
	memset(dp, 0x3f, sizeof(dp));
	for (int j = 0; j < 3; ++j) {
		dp[0][0][0][j] = 0;
	}
	for (int i = 0; i <= cnt[0]; ++i) {
		for (int j = 0; j <= cnt[1]; ++j) {
			for (int k = 0; k <= cnt[2]; ++k) {
				for (int c = 0; c < 3; ++c) {
					if (dp[i][j][k][c] < 1e9) {
						auto cost = [&](int p) {
							return sf[0][p][i] + sf[1][p][j] + sf[2][p][k];
						};
						if (c != 0 && i + 1 <= cnt[0]) {
							dp[i + 1][j][k][0] = min(dp[i + 1][j][k][0], dp[i][j][k][c] + cost(pos[0][i]));
						}
						if (c != 1 && j + 1 <= cnt[1]) {
							dp[i][j + 1][k][1] = min(dp[i][j + 1][k][1], dp[i][j][k][c] + cost(pos[1][j]));
						}
						if (c != 2 && k + 1 <= cnt[2]) {
							dp[i][j][k + 1][2] = min(dp[i][j][k + 1][2], dp[i][j][k][c] + cost(pos[2][k]));
						}
					}
				}
			}
		}
	} 
	int res = *min_element(dp[cnt[0]][cnt[1]][cnt[2]], dp[cnt[0]][cnt[1]][cnt[2]] + 3);
	cout << (res > 1e9 ? -1 : res);
	return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 55 / 55
• Subtask 3: 15 / 15
• Subtask 4: 25 / 25