# Job interviewer - If you have only 1 question tldr; If you had only one question to judge the quality of the technical candidate for your startup, what would that question be?

This is the choice of a question of Asen who I chatted to some minutes ago.

We have two numbers - 36 and 48. Write a function which receives as an input one of these numbers, and returns the other. Important: You are not allowed to use any of these - if clauses, loops and data structures.

### Here are 3 example solutions

Input

Input: 36, Output: 48.

Input: 48, Output: 36.

1. Use sum

2. Use a string

3. Use text files

Here is the logic and pseudo code for the threee solutions :arrow_down:

#### Use sum

• sum up the two numbers
• return the sum of the two numbers minus the input number
``````two_num_sum = 36 + 48

def return_the_other_number(this_number, two_num_sum):
return two_num_sum - this_number
``````

#### Use a string

• Store the two numbers in a sequence in a string.
• Remove the input number from that string
• Return the remaining string
``````def return_the_other_number(this_number):
this_str_number = str(this_number)
num_string = "3648"

return int(num_string.replace(this_str_number, ""))
``````

#### Use text files

• create two text files - named `<number>.txt`. The content of the file would be the other number
• return the calue written in the text file with the name of the input number
``````# 36.txt
48
``````
``````def return_the_other_number(this_number):
filename = str(this_number) + ".txt"

with open(filename, "r") as fin: