RT
我枯了　

我感觉我真没写挂，精度爆炸

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

#define R register
#define LL long long
const int inf = 0x3f3f3f3f;
const int N = 2000 + 5;
const double eps = 1e-9;

inline int read() {
	char a = getchar(); int x = 0,f = 1;
	for(;a > '9' || a < '0';a = getchar()) if(a == '-') f = -1;
	for(;a >= '0' && a <= '9'; a = getchar()) x = x * 10 + a - '0';
	return x * f;
}

int n, a, b;
long double p[N], u[N];
long double f[N];
int cnt1[N], cnt2[N];

inline bool Check(double v1,double v2) {
	memset(f, 0, sizeof(f));
	memset(cnt1, 0, sizeof(cnt1));
	memset(cnt2, 0, sizeof(cnt2));
	for(R int i = 1;i <= n; i ++) {
		f[i] = f[i - 1];
		cnt1[i] = cnt1[i - 1];
		cnt2[i] = cnt2[i - 1];
		if(f[i - 1] + p[i] - v1 > f[i]) {
			f[i] = f[i - 1] + p[i] - v1;
			cnt1[i] = cnt1[i - 1] + 1;
			cnt2[i] = cnt2[i - 1];
		}
		if(f[i - 1] + u[i] - v2 > f[i]) {
			f[i] = f[i - 1] + u[i] - v2;
			cnt1[i] = cnt1[i - 1];
			cnt2[i] = cnt2[i - 1] + 1;
		}
		if(f[i - 1] + p[i] + u[i] - p[i] * u[i] - v1 - v2 > f[i]) {
			f[i] = f[i - 1] + p[i] + u[i] - p[i] * u[i] - v1 - v2;
			cnt1[i] = cnt1[i - 1] + 1;
			cnt2[i] = cnt2[i - 1] + 1;
		}
	}
	return cnt2[n] <= b;
}

long double tl;

inline bool check(double md) {
	long double l = 0, r = 1;
	for(R int i = 1; i <= 50; i ++) {
		long double mid = (l + r) / 2;
		if(Check(md, mid)) r = mid;
		else l = mid;
	}
	tl = l;
	return cnt1[n] <= a;
}


int main() {
	freopen("a.in","r",stdin);
	freopen("b.out","w",stdout);
	n = read(); a = read(); b = read();
	for(R int i = 1; i <= n; i ++) scanf("%Lf", & p[i]);
	for(R int i = 1; i <= n; i ++) scanf("%Lf", & u[i]);
	long double l = 0, r = 1;
	for(R int i = 1; i <= 50; i ++) {
		long double mid = (l + r) / 2;
		if(check(mid)) r = mid;
		else l = mid;
	}
	//printf("%d %d\n", cnt1[n], cnt2[n]);
	printf("%.5Lf\n", f[n] + l * a + tl * b);
	return 0;	
}