Cod sursa(job #1738260)

Utilizator ionanghelinaIonut Anghelina ionanghelina Data 6 august 2016 11:51:49
Problema Secventa 3 Scor 70
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.33 kb
#include<bits/stdc++.h>
#define INF 30000000
#define maxN 30005
using namespace std;
deque<int> q;
double *s,*m;
int n,a[maxN],b[maxN],u,l;
double val(double r)
{
    s[0]=0;
    for(int i=1;i<=n;i++)
    {
        s[i]=s[i-1]+a[i]-r*b[i];
    }
    while (!q.empty()) q.pop_front();
    int d=u-l+1;
    for(int i=1;i<=n;i++)
    {
        while (!q.empty() && s[q.back()]>=s[i])
        {
            q.pop_back();
        }
        q.push_back(i);
        while (q.front()<=(i-d)) q.pop_front();
        if (i>=d)
        {
            m[i]=s[q.front()];
        }
    }
    double maxim=-INF;
    for(int i=l;i<=u;i++)
    {
        if (s[i]>maxim) maxim=s[i];
    }
    for(int i=(u+1);i<=n;i++)
    {
        if ((s[i]-m[i-l])>maxim) maxim=s[i]-m[i-l];
    }
    return maxim;
}
int main()
{
    freopen("secv3.in","r",stdin);
    freopen("secv3.out","w",stdout);
    scanf("%d%d%d",&n,&l,&u);
    s=new double [n+5];
    m=new double [n+5];
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&a[i]);
    }
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&b[i]);
    }
    double ls=0;
    double ld=INF;
    double mid;
    while ((ld-ls)>=0.001)
    {
        mid=(ls+ld)/2;
        if(val(mid)>=0) ls=mid;
            else ld=mid;
    }
    printf("%.2lf\n",mid);
    return 0;
}