Recap: Sector Scan

Combine recursion, matrices (2D lists), and binary search

Mission: Sector Scan

A long-range scan returns a sector map as a 2D grid (a list of lists) stored in a variable named sector, where:

• 0 = open space
• 1 = debris
• 2 = beacon

Pull together everything from this chapter: matrices, recursion, and binary search:

count_beacons(sector): use nested loops on the grid to count how many beacons (the 2s) it contains.

flatten_sorted(sector): collapse the 2D grid into a sorted list of the unique values that appear in it.

find_value(sorted_list, target): use recursive binary search to check whether a value is in the sorted list. Return True or False.

Test with:

print(f"Beacons: {count_beacons(sector)}")
flat = flatten_sorted(sector)
print(f"Unique values: {flat}")
print(f"Has beacon value: {find_value(flat, 2)}")
print(f"Has value 3: {find_value(flat, 3)}")

Output

Beacons: 1
Unique values: [0, 1, 2]
Has beacon value: True
Has value 3: False