Facebook New Grade SWE Interview

facebook_phone_1_2018.py

# Welcome to Facebook!

# This is just a simple shared plaintext pad, with no execution capabilities.

# When you know what language you'd like to use for your interview,
# simply choose it from the dropdown in the top bar.

# Enjoy your interview!

## Move all nonzero integers to left of an array and return the number of nonzero integers

[0, -1, 0, 3, 0]

[-1, 3, 0, 0, 0]
[3, -1, 0, 0, 0]
return 2

##

def endZeroes(arr):
    length = len(arr)
    count = 0
    
    for i in range(length):
        if arr[i] != 0:
            arr[count] = arr[i]
            count += 1
            
    non_zero_count = count
    
    ## we have copied all non zero elements to front of array

            
    while count < length:
        arr[count] = 0
        count += 1
        
    return non_zero_count - count


first = 0
last = length - 1

if arr[i] == 0:
    arr[last -= 1] = arr[i]
else:
    arr[first += 1] = arr[i]

arr = [-1, 3, 0, 0, 0]

# length: 5
# count: 2
# i: 4


## Lexographic compare between 2 strings with consecutive digits treated as a single element, return the "smaller" string (if equal, return either string)

"a9", ""

"a9", "a11"

normal alphabetical comparison:
a9
a11 <<<<

modified alphabetical comparison:
a 9   <<<<
a 11

[a-z0-9]

letters < numbers
a < z < 0 < 9 < ...

a007 == a7

'''
[a, 9]
[a, 1, ,1]
'''


def squashDigits(arr):
    new_arr = []
    for i in len(arr):
        if !arr[i].isDigit():
            new_arr.append(item)
        else:
            current_num = ""
            current_num += arr[i]
            
            while i < len(arr) and new_arr[i + 1].isDigit():
                current_num += new_arr[i + 1]
                new_arr.append(int(current_num))
    return new_arr

# ["a", "9"]
# ["a", "11"]
# "009" vs. "11"

def stringStringCompare(a, b):
    
    if a is None or b is None:
        return -1
    
    if a == "":
        return a:
    elif b == "":
        return b
    else:
        # guarentee a is longer string
        if len(a) < len(b): # a = "1111111" b = "a1" len(a) > len(b) - len(arr_a) = 1, len(arr_b) = 2
            a, b = b, a
        
        arr_a = squashDigits(a.split())
        arr_b = squashDigits(b.split())
        
        
        for i in range(arr_a): # << longer array
            first = arr_a[i]
            second = arr_b[i]
            
            # both are ints
            if first.isdigit() && second.isdigit():
                if first < second:
                    return a
            ## both are strings
            elif first.isalpha() && second.isalpha():
                if first < second:
                    return a
            ## first is string
            elif first.isalpha() && second.isdigit():
                # assume we don't know how comp works between different types
                return a
            ## second is string
            elif first.isdigit() && second.isalpha():
                return b
            
        # the same strings
        return b
            
# ["a", 9]
# ["a", 9, "b"]