cf739E Gosha is hunting (flows)

using namespace std;
const double eps=1e-8;
const int maxn=2000+5;
int n,a,b;
struct {
    int to;
    double cost;int cap,rev;
    edge(int to=0,double cost=0,int cap=0,int rev=0): to(to),cost(cost),cap(cap),rev(rev) {}
};
vector<edge> g[maxn];
void addedge(int from,int to,int cap,double cost)
{
    cost=-cost;
    g[from].push_back(edge(to,cost,cap,g[to].size()));
    g[to].push_back(edge(from,-cost,0,g[from].size()-1));
}
double p[maxn],u[maxn];
int S,T,A,B;
#define MP make_pair
bool inque[maxn];
double dis[maxn];
int preve[maxn],prevv[maxn];
queue<int > q;
double spfa()
{
    for(int i=S;i<=B;i++) dis[i]=1e60,inque[i]=false;
    dis[S]=0;inque[S]=true;
    while(!q.empty()) q.pop();
    q.push(S);
    memset(prevv,0,sizeof(prevv));memset(preve,0,sizeof(preve));
    while(!q.empty())
    {
        int u=q.front();q.pop();inque[u]=false;
        for(int i=0;i<(int)g[u].size();i++){
            edge &e=g[u][i];
            if(e.cap && dis[e.to]-(dis[u]+e.cost)>eps) {
                dis[e.to]=dis[u]+e.cost;
                preve[e.to]=i,prevv[e.to]=u;
                if(!inque[e.to]){
                    inque[e.to]=true;
                    q.push(e.to);
                }
            }
        }
    }
    if(dis[T]>=1e60) return 0;
    int gap=INT_MAX;
    for(int i=T;i!=S;i=prevv[i]) gap=min(gap,g[prevv[i]][preve[i]].cap);
    for(int i=T;i!=S;i=prevv[i]){
        edge &e=g[prevv[i]][preve[i]];
        e.cap-=gap;
        g[i][e.rev].cap+=gap;
    }
    return dis[T]*(double)gap;
}
double MaxcostMaxflow()
{
    double res=0,ret=0;
    while((res=spfa())!=0)  ret+=res,res=0;
    return ret;
}
int main()
{
    scanf("%d%d%d",&n,&a,&b);
    for(int i=1;i<=n;i++) scanf("%lf",&p[i]);
    for(int i=1;i<=n;i++) scanf("%lf",&u[i]);
    S=0,T=n+1,A=n+2,B=n+3;
    addedge(S,A,a,0),addedge(S,B,b,0);
    for(int i=1;i<=n;i++) addedge(A,i,1,p[i]),addedge(B,i,1,u[i]),addedge(i,T,1,0),addedge(i,T,1,-p[i]*u[i]);
    printf("%.4lfn",-MaxcostMaxflow());
    return 0;
}