Sorting

Bubble sort vs Quick sort

Bubble sort and Quick sort both put an array in order, in different ways. Bubble sort: swap neighbors that are out of order. Quick sort: divide and conquer: partition around a pivot. In the worst case both take O(n²), so the choice comes down to the other differences below.

At a glance

Property	Bubble sort	Quick sort
Technique	Swap neighbors that are out of order	Divide and conquer: partition around a pivot
Best case time	O(n)	O(n log n)
Average case time	O(n²)	O(n log n)
Worst case time	O(n²)	O(n²)
Extra space	O(1)	O(log n)
Stable (equal values keep their order)	Yes	No
In place (no extra array)	Yes	Yes
Needs sorted input	No	No

Choose bubble sort when

you want the simplest sort to explain, on tiny or almost sorted data.

Avoid it when

the data is large.

Choose quick sort when

you want a fast in-place sort on typical data.

Avoid it when

you need a worst-case guarantee or a stable sort.

The same inputs, counted

These numbers come from running both real implementations: operations (comparisons plus writes, a swap counting as two writes).

Input	Bubble sort	Quick sort
Mixed	40	31
Already sorted	6	75
Reversed	63	51
Nearly sorted	13	65
Duplicates	47	29

Bubble sort vs Quick sort

At a glance

Choose bubble sort when

Avoid it when

Choose quick sort when

Avoid it when

The same inputs, counted

See them run

More comparisons

Bubble sort vs Quick sort

At a glance

When to choose each

Choose bubble sort when

Avoid it when

Choose quick sort when

Avoid it when

The same inputs, counted

See them run

More comparisons