Sorting algorithms (bubble, selection) in Intro to Computing - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to swap two elements in a list.

Intro to Computing

temp = arr[[1]]
arr[[1]] = arr[[2]]
arr[[2]] = temp

Drag options to blanks, or click blank then click option'

Ai

Bj

C0

Dlen(arr)

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping with wrong indices

Using the same index twice

To swap elements at positions i and j, you first save the value at i, then assign the value at j to i, and finally assign the saved value to j.

2fill in blank

medium

Complete the code to compare two adjacent elements in bubble sort.

Intro to Computing

if arr[[1]] > arr[[2]]:

Drag options to blanks, or click blank then click option'

Ai

Bi+1

Cj

Dj+1

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing wrong indices

Using outer loop variable instead of inner loop variable

In bubble sort, you compare element at position j with the next element j+1 to decide if they need to be swapped.

3fill in blank

hard

Fix the error in the selection sort inner loop condition.

Intro to Computing

for j in range(i+1, [1]):

Drag options to blanks, or click blank then click option'

Ai

Blen(arr)-1

Clen(arr)

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using len(arr)-1 which skips last element

Using wrong start index

The inner loop in selection sort runs from i+1 to the end of the list, which is len(arr). Using len(arr)-1 would miss the last element.

4fill in blank

hard

Fill both blanks to complete the bubble sort outer and inner loops.

Intro to Computing

for i in range([1]):
    for j in range([2] - i - 1):

Drag options to blanks, or click blank then click option'

Alen(arr)

Blen(arr) - 1

Clen(arr) - i

Dlen(arr) + 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using len(arr) - 1 for outer loop

Incorrect inner loop range causing index errors

The outer loop runs from 0 to len(arr). The inner loop runs from 0 to len(arr) - i - 1 to avoid checking already sorted elements at the end.

5fill in blank

hard

Fill all three blanks to complete the selection sort swap step.

Intro to Computing

min_idx = [1]
for j in range(i+1, [2]):
    if arr[j] < arr[min_idx]:
        min_idx = j
arr[[3]], arr[i] = arr[i], arr[[3]]

Drag options to blanks, or click blank then click option'

Ai

Blen(arr)

Cmin_idx

Dj

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping wrong indices

Incorrect loop range

Not updating min_idx correctly

In selection sort, you start with min_idx = i. The inner loop runs to len(arr). After finding the minimum index, you swap arr[min_idx] with arr[i].