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:

Practice problems:

  1. 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")
    
  2. 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)
  3. Approximately how many iterations will binary search need to find a value in a list of 1 million items?
  4. Place these algorithm classes in order from best to worst: N, logN, N*N, NlogN
  5. What is log(1024,2) in python? What about log(2048,2)?
  6. 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
    #############################################
    
  7. 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      ----------------
    
    
    
    
    
    

  8. 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(",")
    
    

  9. 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]