CS61A Homework 1- Variables & Functions, Control Solution

Instructions
Download hw01.zip.
Using Ok: If you have any questions about using Ok, please refer to this guide.
Readings: You might find the following references useful:
Section 1.1
Section 1.2
Section 1.3
Section 1.4
Section 1.5
Grading: Homework is graded based on correctness. Each incorrect problem will decrease the total score by one point. There is a homework recovery policy as stated in the syllabus. This homework is out of 2 points.
Required Questions
Welcome Forms
Q1: Welcome Forms
Please fill out both the Syllabus Quiz, which is based off of our policies found on the course syllabus, as well as the optional Welcome Survey.
Parsons Problems
To work on these problems, open the Parsons editor:
python3 parsons
Q2: k in Num
Write a function k_in_num which takes in two integers, k and num. k_in_num returns True if num has the digit k and returns False if num does not have the digit k. 0 is considered to have no digits.
```py def k_in_num(k, num): """ Complete k_in_num, a function which returns True if num has the digit k and returns False if num does not have the digit k. 0 is considered to have no digits.
>>> k_in_num(3, 123) # .Case 1
True
>>> k_in_num(2, 123) # .Case 2
True
>>> k_in_num(5, 123) # .Case 3
False
>>> k_in_num(0, 0) # .Case 4
False
"""
"*** YOUR CODE HERE ***"
```
Code Writing Problems
Q3: A Plus Abs B
Python's operator module defines binary functions for Python's intrinsic arithmetic operators. For example, calling operator.add(2,3) is equivalent to calling the expression 2 + 3 ; both will return 5.
```py def a_plus_abs_b(a, b): """Return a+abs(b), but without calling abs.
>>> a_plus_abs_b(2, 3)
5
>>> a_plus_abs_b(2, -3)
5
>>> a_plus_abs_b(-1, 4)
3
>>> a_plus_abs_b(-1, -4)
3 """ if b < 0:
f = _____ else: f = _____ return f(a, b)
```
Use Ok to test your code:
python3 ok -q a_plus_abs_b
Q4: Two of Three
Write a function that takes three positive numbers as arguments and returns the sum of the squares of the two smallest numbers. Use only a single line for the body of the function.
```py def two_of_three(i, j, k): """Return mm + nn, where m and n are the two smallest members of the positive numbers i, j, and k.
>>> two_of_three(1, 2, 3)
5
>>> two_of_three(5, 3, 1)
10
>>> two_of_three(10, 2, 8)
68
>>> two_of_three(5, 5, 5)
50 """ return _____
```
Hint: Consider using the max or min function: ```py
max(1, 2, 3) 3 min(-1, -2, -3) -3 ```
Use Ok to test your code:
python3 ok -q two_of_three Q5: Largest Factor
Write a function that takes an integer n that is greater than 1 and returns the largest integer that is smaller than n and evenly divides n.
```py def largest_factor(n): """Return the largest factor of n that is smaller than n.
>>> largest_factor(15) # factors are 1, 3, 5
5
>>> largest_factor(80) # factors are 1, 2, 4, 5, 8, 10, 16, 20, 40
40
>>> largest_factor(13) # factor is 1 since 13 is prime 1
"""
"*** YOUR CODE HERE ***"
```
Hint: To check if b evenly divides a, you can use the expression a % b == 0, which can be read as, "the remainder of dividing a by b is 0."
Use Ok to test your code:
python3 ok -q largest_factor
Submit
Make sure to submit this assignment by running:
python3 ok --submit