CS21: Quiz 5 Study Guide

In addition to the concepts below, you should also know the concepts from Quiz 1, Quiz 2, Quiz 3, and Quiz 4. Many of the earlier concepts -- especially functions -- are fundamental to what we've been studying recently.

You should understand the following terms:

Top-Down Design
Function stub
Searching: linear vs binary search
Sorting: selection, bubble, insertion
Analysis of algorithms (number of steps)
Big-O notation (O(N) vs O(logN), etc)

Practice problems:

Imagine you are writing a function to process grade data (call it nameAndGrade()). Write a function stub to process a string such as "jeff,11-15-2013,97.5" and return a list with just the name and grade: ["jeff", 97.5]. Implement your function and test it with the following code:
```
  print nameAndGrade("jeff,11-15-2013,97.5")
  print nameAndGrade("andy,11-17-2013,83.0")
  print nameAndGrade("jason,12-15-2013,76.7")
```
True/False questions:
- Linear search requires a number of steps proportional to the size of the list being searched (T/F)
- The python in operator performs a binary search (T/F)
- Binary search is an NlogN algorithm (T/F)
- The number of times N can be divided by 2 is log base-two of N (T/F)
Approximately how many iterations will binary search need to find a value in a list of 1 million items?
Place these algorithm classes in order from best to worst: N, logN, N*N, NlogN
What is log(1024,2) in python? What about log(2048,2)?

How many steps are required for each of the following?

#############################################
for i in range(n):
  for j in range(n):
    print i, j
#############################################
while n > 1:
  print n
  n = n/2
#############################################
for i in range(n):
  for j in range(10):
    print i, j
#############################################

Show the index values for low, high, and mid for each step in searching the list L for the value x using binary search.

x = 99
L = [-20, -12, -4, 1, 7, 44, 45, 46, 58, 67, 99, 145]     low   mid   high
       0    1   2  3  4   5   6   7   8   9  10   11      ----------------

Given the following assignments:

   ls = ["fish", "squirrel", "cat", "dog", "monkey", "pony"]
   s = "a,b,c,d,e"

What are the value and type of the following expressions:

  (1) ls[3]
  (2) ls[3] > "apple" 
  (3) ls[3][1]
  (4) 'b' < 'f'
  (5) len(ls[5])
  (6) range(len(ls))
  (7) range(len(ls[0]))
  (8) s.split(",")

If you are running selectionSort() on the following list, L:

L = [9, 35, 18, 200, 0, 6, 43, 21]

Which of the following represents L after 3 iterations of the outer loop in selectionSort()?

A. [0, 6, 9, 18, 21, 35, 43, 200]
B. [0, 6, 9, 200, 18, 35, 43, 21]
C. [0, 9, 35, 18, 200, 6, 43, 21]
D. [0, 6, 9, 35, 200, 18, 43, 21]