暴力枚举滴油的顺序，模拟即可。

时间复杂度 $\mathcal{O}(n!\times n)$

#include <bits/stdc++.h>
using namespace std;
const int N = 10, nk[] = {0, 1, 2, 6, 24, 120, 720};
int x[N], y[N], perm[N], n, x1, y_1, x2, y2;
double ans, r[N];
double dis(int u, int v) {
	return sqrt((x[u] - x[v]) * (x[u] - x[v]) + (y[u] - y[v]) * (y[u] - y[v]));
}
int main() {
	cin >> n >> x1 >> y_1 >> x2 >> y2;
	ans = abs(x1 - x2) * abs(y_1 - y2);
	for (int i = 1; i <= n; i ++)
		cin >> x[i] >> y[i], perm[i] = i;
	for (int i = 1; i <= nk[n]; i ++) {
		double sum = abs(x1 - x2) * abs(y_1 - y2);
		for (int j = 1; j <= n; j ++) {
			double R = min(min(abs(x[perm[j]] - x1), abs(x[perm[j]] - x2)), min(abs(y[perm[j]] - y_1), abs(y[perm[j]] - y2)));
			for (int k = 1; k < j; k ++)
				R = min(R, max(dis(perm[j], perm[k]) - r[perm[k]], 0.0));
			r[perm[j]] = R, sum -= R * R * 3.1415926;
		}
		ans = min(ans, sum), next_permutation(perm + 1, perm + 1 + n);
	}
	printf("%.0lf", ans);
	return 0;
}