CS basics

Question 1

Data structures e.g. Stack vs queue

Answer 1

stack uses LIFO
queue uses FIFO

Question 2

Describe heap

Answer 2

heap is a data structure made up of “nodes” that contain values.
tree

Question 3

Boolean operations, short circuits in Boolean operations

Answer 3

, & , ^ , ! , || , && , == , !=
circuit - when all conditions are not checked if not needed: && and ||

Question 4

Recursion, tail recursion, mutual recursion

Answer 4

head - recursive call before other processing in the function
tail - the processing occurs before the recursive call.
Mutual recusion - two objects are defined in terms of each other

Question 5

Sorting algorithms

Answer 5

Bubble sort - compare each pair
Insertion Sort - compare each with previous
Selection Sort - fin mininum. put in start
Merge Sort - divide into sublists and sort
Quick Sort - take element. move less to the left, move more to the right. repeat

Question 6

Complexity of algorithms, big O notation

Answer 6

big-O notation is an asymptotic upper bound

Question 7

Trees, graphs and ways to traverse graph

Answer 7

tree is an undirected graph in which any two vertices are connected by exactly one path

Question 8

Binary tree

Answer 8

each node has up to two child nodes

Question 9

Search in binary tree

Answer 9

1. Start from root.
2. Compare the inserting element with root, if less than root, then recurse for left, else recurse for right.
3. If element to search is found anywhere, return true, else return false.

Question 10

Dynamic programming

Answer 10

is a method for solving a complex problem by breaking it down into a collection of simpler subproblems

Question 11

How would you fix a cyclic dependency

Answer 11

Use interfaces

Question 12

What is the difference between static and dynamic typing? Duck typing?

Answer 12

Static typing means that type errors are reported at compile time
dynamic typing means that type errors are reported at runtime
duck typeing - object supports operation. no matter what type