kedaOJ#P0646. [NOIP2016提高组] 换教室

题目

P0646. [NOIP2016提高组] 换教室

思路

简单很难的D规划P

代码

#include<bits/stdc++.h>
using namespace std;
int dis[305][305];
constexpr int _SIZE = 2e3;
int n, m, v, e;
int c[_SIZE + 5], d[_SIZE + 5];
double k[_SIZE + 5];
double f[2][_SIZE + 5];
signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> m >> v >> e;
	memset(dis, 0x3f, sizeof dis);
	for (int i = 1; i <= n; i++) cin >> c[i];
	for (int i = 1; i <= n; i++) cin >> d[i];
	for (int i = 1; i <= n; i++) cin >> k[i];
	for (int i = 1; i <= v; i++) dis[i][i] = 0;
	for (int i = 1; i <= e; i++) {
		int u, v, l;
		cin >> u >> v >> l;
		int temp = min(dis[u][v], l);
		dis[u][v] = dis[v][u] = temp;
	}
	for (int k = 1; k <= v; k++)
		for (int i = 1; i <= v; i++)
			for (int j = 1; j <= v; j++)
				dis[i][j] = min(dis[i][j], dis[i][k] + dis[k][j]);
	memset(f, 127, sizeof(f));
	f[0][0] = 0, f[1][1] = 0;
	for (int i = 2; i <= n; i++) {
		for (int j = i; j >= 0; j--) {
			f[0][j] = min(f[1][j] + k[i - 1] * dis[d[i - 1]][c[i]] +
			              (1 - k[i - 1]) * dis[c[i - 1]][c[i]],
			              f[0][j] + dis[c[i - 1]][c[i]]);
			if (j == 0) continue;
			f[1][j] = min(f[0][j - 1] + k[i] * dis[c[i - 1]][d[i]] +
			              (1 - k[i]) * dis[c[i - 1]][c[i]],
			              f[1][j - 1] + k[i - 1] * k[i] * dis[d[i - 1]][d[i]] +
			              k[i - 1] * (1 - k[i]) * dis[d[i - 1]][c[i]] +
			              (1 - k[i - 1]) * k[i] * dis[c[i - 1]][d[i]] +
			              (1 - k[i - 1]) * (1 - k[i]) * dis[c[i - 1]][c[i]]);
		}
	}
	double ans = 1145141919810.0;
	for (int i = 0; i <= m; i++) ans = min({ans, f[0][i], f[1][i]});
	cout << fixed << setprecision(2) << ans << '\n';
	return 0;
}