Facebook Interview Question: Write a function that takes i... | Glassdoor

Interview Question

Data Scientist Interview Menlo Park, CA

Write a function that takes in two sorted lists and outputs

  a sorted list that is their union.
sql, product, science, analytics, python, data

Interview Answer

9 Answers


f(a,b) { return sort(unique(a,b)) }

Anonymous on Jun 14, 2013

def sortedUnion(list1,list2):
    list3 = [x for x in list1 if x in list2]
    return sorted(list(set(list3)))

Anonymous on Sep 6, 2013

google merge sort

Anonymous on Nov 13, 2013

write 2 helpers: 1) INSERT(A, b) = put element b within A in the sort order
2) DEL(A, a) = delete element a from A

Then do this recursion:
f(A,B) : if max(A) <= min(B) return [A B]
            else { B = INSERT(B, max(a));
                      A = DEL(A, max(a);

something like that. try coding and testing. I haven't.

TheProf on Aug 9, 2014

Oops, check/write a termination condition

TheProf on Aug 9, 2014

On Python, you could do:

from sets import Set

def merge_sort(a,b):
    return sorted( Set(a).union(Set(b)) )

wp on Sep 26, 2014

def sorted_union(list1, list2):
    return sorted_union

JC on Jun 10, 2015

Second part of merge sort. Don't answer with sort(a), etc. Anyone can do that...

def merge(A, B):
    sorted_list = []

    while i < len(A) and j < len(B):
        if A[i] <= B[j]:
            i += 1
            j += 1

    if i < len(A):
    elif j < len(B):

    return sorted_list

Anonymous on Jul 30, 2016

I assumed that we can not use any "sort" function and we want it with linear time.

so here it is:

def my_sort(list_a, list_b):
            if len(list_a) ==0:
                return list_b
            elif len(list_b) ==0:
                return list_a
                if list_a[-1] > list_b[-1]:
                    return( my_sort(list_a[0:-1], list_b) + [list_a.pop(-1)])
                    return(my_sort(list_a,list_b[:-1]) + [list_b.pop(-1)])

Anonymous on Aug 25, 2016

Add Answers or Comments

To comment on this, Sign In or Sign Up.