Problem:
Score : 300 points

Problem Statement

You've come to your favorite store Infinitesco to buy some ice tea.

The store sells ice tea in bottles of different volumes at different costs.
Specifically, a 0.25-liter bottle costs Q yen, a 0.5-liter bottle costs H yen, a 1-liter bottle costs S yen, and a 2-liter bottle costs D yen.
The store has an infinite supply of bottles of each type.

You want to buy exactly N liters of ice tea. How many yen do you have to spend?

Constraints

1 \leq Q, H, S, D \leq 10^8

1 \leq N \leq 10^9

All input values are integers.

Input

Input is given from Standard Input in the following format:

Q H S D
N

Output

Print the smallest number of yen you have to spend to buy exactly N liters of ice tea.

Sample Input 1

20 30 70 90
3

Sample Output 1

150

Buy one 2-liter bottle and two 0.5-liter bottles. You'll get 3 liters for 90 + 30 + 30 = 150 yen.

Sample Input 2

10000 1000 100 10
1

Sample Output 2

100

Even though a 2-liter bottle costs just 10 yen, you need only 1 liter.
Thus, you have to buy a 1-liter bottle for 100 yen.

Sample Input 3

10 100 1000 10000
1

Sample Output 3

40

Now it's better to buy four 0.25-liter bottles for 10 + 10 + 10 + 10 = 40 yen.

Sample Input 4

12345678 87654321 12345678 87654321
123456789

Sample Output 4

1524157763907942

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;

public class Main{
	
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
  	long[] a=new long[4],b=new long[4];
    long sum=0;
    for(int i=0;i<4;i++){
      a[i]=sc.nextLong();
    }
    long n=sc.nextLong();
    b[0]=a[0]*8;
    b[1]=a[1]*4;
    b[2]=a[2]*2;
    b[3]=a[3];
    int f=0;
    for(int i=0;i<2;i++){
      if(b[i]>b[i+1]){
        f=i+1;
        
      }else{
        f=i;
        b[i+1]=b[i];
      }
    }
    if(b[f]>=b[2]){
      for(int i=0;i<n/2;i++){
        sum+=a[2];
      }
      if(n%2==1){
        sum+=a[f];
      }
    }else{
      for(int i=0;i<n;i++){
        sum+=a[f];
      }
    }
    System.out.println(sum);
  }
}