Given the array of strings A,

you need to find the longest string S which is the prefix of ALL the strings in the array.

Longest common prefix for a pair of strings S1 and S2 is the longest string S which is the prefix of both S1

and S2.

For Example, longest common prefix of "abcdefgh" and "abcefgh" is "abc".

Input Format

The only argument given is an array of strings A.

Output Format

Return longest common prefix of all strings in A.

For Example

Input 1:

A = ["abcdefgh", "aefghijk", "abcefgh"]

Output 1:

"a"

Explanation 1:

Longest common prefix of all the strings is "a".

Input 2:

A = ["abab", "ab", "abcd"];

Output 2:

"ab"

Explanation 2:

Longest common prefix of all the strings is "ab".

Please note that python code for above question should pass large test cases, and all corner test cases, reasoning for below MCQs is also needed, please dont copy (unhelpful if copied or didn't answer all)

1. Is the following Python code valid?

>>> a,b,c=1,2,3

>>> a,b,c

a) Yes, [1,2,3] is printed

b) No, invalid syntax

c) Yes, (1,2,3) is printed

d) 1 is printed

2. What will be the output of the following Python code?

a = ('check',)

n = 2

for i in range(int(n)):

a = (a,)

print(a)

a) Error, tuples are immutable

b)

(('check',),)

((('check',),),)

c) (('check',)'check',)

d)

(('check',)'check',)

((('check',)'check',)'check',)

3. Is the following Python code valid?

>>> a,b=1,2,3

a) Yes, this is an example of tuple unpacking. a=1 and b=2

b) Yes, this is an example of tuple unpacking. a=(1,2) and b=3

c) No, too many values to unpack

d) Yes, this is an example of tuple unpacking. a=1 and b=(2,3)

4. What will be the output of the following Python code?

>>> a=(1,2)

>>> b=(3,4)

>>> c=a+b

>>> c

a) (4,6)

b) (1,2,3,4)

c) Error as tuples are immutable

d) None

5. What will be the output of the following Python code?

>>> a,b=6,7

>>> a,b=b,a

>>> a,b

a) (6,7)

b) Invalid syntax

c) (7,6)

d) Nothing is printed

6. What will be the output of the following Python code?

>>> import collections

>>> a=collections.namedtuple('a',['i','j'])

>>> obj=a(i=4,j=7)

>>> obj

a) a(i=4, j=7)

b) obj(i=4, j=7)

c) (4,7)

d) An exception is thrown

7. Tuples can't be made keys of a dictionary.

a) True

b) False

8. Is the following Python code valid?

>>> a=2,3,4,5

>>> a

a) Yes, 2 is printed

b) Yes, [2,3,4,5] is printed

c) No, too many values to unpack

d) Yes, (2,3,4,5) is printed

9. What will be the output of the following Python code?

>>> a=(2,3,1,5)

>>> a.sort()

>>> a

a) (1,2,3,5)

b) (2,3,1,5)

c) None

d) Error, tuple has no attribute sort

10. Is the following Python code valid?

>>> a=(1,2,3)

>>> b=a.update(4,)

a) Yes, a=(1,2,3,4) and b=(1,2,3,4)

b) Yes, a=(1,2,3) and b=(1,2,3,4)

c) No because tuples are immutable

d) No because wrong syntax for update() method