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Question 1

High-level: Binary Search

Answer 1

base case:
return nil if empty array

gen case:
probe mid element with probe_index

return index if probe == target

bsearch(left) if target < probe

if target > probe
answer = bsearch(right)

answer.nil? ? nil : probe_index + 1 + answer

Question 2

Why do sorts always take a proc?

Answer 2

To control the sort order (and to sort objects by attribute values).

Question 3

How do you move selected text up/down/left/right in Atom?

Answer 3

cmd + ctrl + arrows

Question 4

What does cmd + ctrl + arrows do in Atom?

Answer 4

moves selected text around

Question 5

Methods that do not reference an instance variable should be written as what type of method?

Answer 5

Class method

Question 6

Outline basic 4-step git workflow

Answer 6

new file in working dir
git add file
file now in staging
git commit
file now in repo
git push
file now in remote repo

Question 7

What’s a more condensed version of git log?

Answer 7

git log –oneline

Question 8

What does git log –oneline do?

Answer 8

Shows a more condensed version of the git log

Question 9

What’s a shortcut to create and switch into a new branch?

Answer 9

git checkout -b newbranch

Question 10

How to see the diff before merging a branch?

Answer 10

git checkout branch

git diff branch-to-merge

Question 11

How do bring a remote repo locally

Answer 11

git clone url

Question 12

What are some abstract data types?

7: 5 star
5-6: 4 star
1-4: 1 star

Answer 12

set
map
queue
tree
binary tree
ternary tree
nary-tree/polytree

Question 13

What is a map ADT?

Answer 13

a set of key/value pairs

Question 14

What two ops exist within a Queue ADT?

High-level: how would you implement one?

Answer 14

enqueue, dequeue

Array
unshift and pop

Question 15

Elegant way to explain the depth of a tree?

Answer 15

Longest path to a leaf node

Question 16

What are two ways to traverse a tree?

Answer 16

DFS, BFS

Question 17

What are DFS and BFS for?

Answer 17

Traversing a tree

Question 18

High-level: How do you perform a BFS?

Answer 18

Add the root to a queue

until the queue is empty, we want to:

1. shift a node off the queue
2. process that node
3. enqueue all of that node’s children into the queue

Question 19

Why would you use BFS over DFS?

Answer 19

If you think the result will be found nearer to the top of the tree, BFS will be much faster.

Question 20

If you think the result will be found nearer to the top of the tree, what type of traverse should you use?

Answer 20

BFS

Question 21

What 3 things make a decent commit message?

Answer 21

present tense capitalized verb
explains the commit
no trailing punctuation

Question 22

What’s wrong with this code:

Class Foo
private
def some_priv_method
end

def initialize
self.some_priv_method
end
end

Answer 22

private method cannot be called with an explicit receiver.

instead, use a relative receiver.