# Hackerrank - Between Two Sets Solution

You will be given two arrays of integers and asked to determine all integers that satisfy the following two conditions:

- The elements of the first array are all factors of the integer being considered
- The integer being considered is a factor of all elements of the second array

These numbers are referred to as being * between* the two arrays. You must determine how many such numbers exist.

For example, given the arrays and , there are two numbers between them: and . , , and for the first value. Similarly, , and , .

**Function Description**

Complete the * getTotalX* function in the editor below. It should return the number of integers that are betwen the sets.

getTotalX has the following parameter(s):

: an array of integers*a*: an array of integers*b*

**Input Format**

The first line contains two space-separated integers, and , the number of elements in array and the number of elements in array .

The second line contains distinct space-separated integers describing where .

The third line contains distinct space-separated integers describing where .

**Constraints**

**Output Format**

Print the number of integers that are considered to be * between* and .

**Sample Input**

```
2 3
2 4
16 32 96
```

**Sample Output**

```
3
```

**Explanation**

2 and 4 divide evenly into 4, 8, 12 and 16.

4, 8 and 16 divide evenly into 16, 32, 96.

4, 8 and 16 are the only three numbers for which each element of a is a factor and each is a factor of all elements of b.

### Solution in Python

```
from math import gcd
def get_hcf(arr):
hcf = arr[0]
for i in arr:
hcf = gcd(hcf,i)
return hcf
def lcm(a,b):
return a*b//gcd(a,b)
def get_lcm(arr):
l = arr[0]
for i in arr:
l = lcm(l,i)
return l
input()
a = list(map(int,input().split()))
b = list(map(int,input().split()))
lcm_a = get_lcm(a)
hcf_b = get_hcf(b)
f = [i for i in range(lcm_a, hcf_b+1) if not hcf_b%i and not i%lcm_a]
print(len(f))
```

**Additional Info.**

- Numbers must be between LCM of a and HCF of b
- Numbers must be a divisor of HCF of b
- Numbers must be divisible by LCM of a

All the numbers between the lcm of a and the hcf of b that divides hcf of b and is divisible by lcm of a, are the required numbers.