Full sort

Sort fully with multiple passes; O(n^2).

Is sorted check

To check if an array is sorted, you iterate over adjacent pairs and verify that each is in the correct order.

If you find even one pair in the wrong order, the array is not sorted. If all pairs are correct, the array is sorted.

Early termination

To optimize bubble sort, if no swap occurs during a pass, the array is sorted and the algorithm can stop. This makes the best case O(n).

This optimization uses a swapped flag: False at the start of a pass, True when a swap occurs. If still False at the end, the loop breaks.

Exercise Is sorted

Write is_sorted(arr). Check neighbors, return True if sorted, False otherwise. Print True with print(is_sorted([1, 2, 3])).

Show example solution

def is_sorted(arr):
    # Check if sorted
    for i in range(len(arr) - 1):
        if arr[i] > arr[i + 1]:
            return False
    return True
print(is_sorted([1, 2, 3]))

Test yourself

Full sort: match the terms

Sorted

Neighbors correct
Pass

Start to end
No swap

Stop
O(n^2)

Worst
What does no swap in a pass mean?
- Array is broken
- Array is sorted
- Array is empty
- Array is too large
Show answer

Array is sorted — No swap means the array is sorted.

Sorted check

If sorted, ____ is returned.

Show answer

If sorted, True is returned.

Next lesson: Summary - Bubble sort

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