Lecture 11

Announcements

• Midterm
  • High points: nth Free Response, 2D List free response, 2D List Code Tracing
  • Low points: Animation and Reasoning Over
    
  • Quiz on Friday -> Adding an ROC section, get points back on the midterm
  • Practice ROC each day
• Talk to me about term project ideas by 7/28 if you want to use external tech
  • Need to know the tech by 8/1
• This week
  • 3 smaller homework assignments
  • Quiz on Friday
• Fluency: we will work on speeding up!
• Tomorrow: Learn the sorting algorithms!

Code from Lecture

def binarySearch(L, target):
    # we assume L is sorted
    start = 0
    end = len(L)
    while(start != end):
        mid = (start + end)//2
        if(L[mid] == target):
            return mid
        elif(L[mid] < target):
            start = mid + 1
        else:
            end = mid
    return -1
    
def repeats(L):
    # return a sorted list of the repeat elements in the list L
    seen = set()
    seenAgain = set()
    for element in L: # N times
        if (element in seen): # O(1)
            seenAgain.add(element) # O(1)
        seen.add(element) # O(1)
    return sorted(seenAgain) # O(Nlog(N))

Lecture

• [10 min] Announcements
• [40 min] Big-O
  • [5 min] go through notes up to sequencing
  • [10 min] sequencing, nesting, composition using notes + examples
    • Practice:
      • Composition: One in the notes
        
      • Mild: 1
      • Sequencing: Prob 6
      • Nesting: Prob 8
  • [10 min] Searching
    • How would you find an element in a list?
    • Can we do it without looking at all the elements?
    • Demo: 3 people be the indicies
  • [5 min] sumOfSquares
  • [<1 min] Talk about table
  • [10 min] Attendance Check + ROC Practice
• [20 min] Sets
  • [2 min] Look at different ways of making sets
  • [5 min] Properties
  • [5 min] Hashing: bucket demo
  • [5 min] isPermutation, repeats
  • [<1 min] Briefly mention operations
• [10 min] Dictionaries
  • [7 min] Go through notes
  • [3 min] areAnagrams (What was the original Big-O?)