Trees and hierarchical data in Intro to Computing - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a root node named 'root' in a simple tree structure.

Intro to Computing

class Node:
    def __init__(self, value):
        self.value = value
        self.children = []

root = Node([1])

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

A"root"

Broot

CNode

Dchildren

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the string value.

Using variable names instead of string literals.

The root node's value should be a string "root" to represent its name. Using quotes makes it a string literal.

2fill in blank

medium

Complete the code to add a child node named 'child1' to the root node's children list.

Intro to Computing

child1 = Node("child1")
root.children.[1](child1)

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Aappend

Bextend

Cinsert

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Using add which is not a list method.

Using extend which expects an iterable, not a single item.

To add a single child node to the list, use the append method.

3fill in blank

hard

Fix the error in the code to correctly print all child node values of the root.

Intro to Computing

for child in root.children:
    print(child.[1])

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Aname

Bchildren

Cvalue

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to print child.children which is a list, not the name.

Using child.name which is not defined.

Each child node stores its name in the value attribute, so printing child.value shows the child's name.

4fill in blank

hard

Fill both blanks to create a dictionary mapping each child's name to the number of its children.

Intro to Computing

child_counts = {child.[1]: len(child.[2]) for child in root.children}

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Avalue

Bchildren

Cname

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using name instead of value for the child's name.

Using count which is not an attribute.

Use child.value to get the child's name and child.children to get its list of children. len() counts how many children it has.

5fill in blank

hard

Fill all three blanks to create a dictionary of grandchildren counts for each child node with more than zero grandchildren.

Intro to Computing

grandchild_counts = {child.[1]: sum(len(grandchild.[2]) for grandchild in child.[3]) for child in root.children if sum(len(grandchild.children) for grandchild in child.children) > 0}

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

Avalue

Bchildren

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up keys and values in the dictionary comprehension.

Using incorrect attribute names like count or name.

The dictionary keys are child names (child.value). For each child, sum the lengths of their grandchildren lists (grandchild.children) to count grandchildren.