dedicated visualizer
Quick Sort
Partitions the array around a pivot and recursively sorts the resulting partitions. This page keeps the runner, chart, and controls focused on a single algorithm so the walkthrough feels calmer than the overview page.
session controls
Compare this algorithm against a related one, turn on quiz mode, or keep the current state in a shareable URL.
current shareable URL
Copy the URL to preserve this exact dataset, target, compare mode, and quiz state.
browse more
Want a different problem or visual mode? Jump back to the catalog and open another dedicated page.
open catalogscenario presets
Load a focused input that reveals a specific behavior quickly instead of hand-editing every value first.
dataset controls
Use your own array, randomize a fresh one, or restore defaults. The same dataset is shared by both panels in compare mode.
Enter up to 12 integers. Values are normalized to the range 1–99 for clean visualization.
chart + counters
The visualization and the live counters stay together so each step is easier to read.
current action · choose pivot
current action
choose pivot
comparisons
0
final 14
swaps
0
final 11
sorted
0
final 8
steps
1 / 35
run summary
Finished in 35 steps. Final order: 1, 2, 3, 5, 6, 7, 8, 9.
comparisons
14
swaps
11
sorted
8
steps
35
current explanation
Quick sort chooses a pivot, partitions around it, and recurses on both sides.
simple explanation
Pick one value, move smaller ones left and larger ones right.
pseudocode
complexity card
best
O(n log n)
average
O(n log n)
worst
O(n²)
space
O(log n)
algorithm notes
intuition
Quick sort wins by placing pivots correctly and shrinking the unsorted problem quickly.
tradeoffs
- Fast in practice with good pivots.
- Worst-case time degrades to O(n²).
- In-place but usually not stable.
when to use it
Use when average-case speed and in-place behavior matter more than stability.
interview tips
- Discuss pivot strategy and how randomized pivots reduce worst-case risk.
- Be ready to explain partition invariants.
what I learned building this
typed definitions
One algorithm schema now drives the catalog, counters, pseudocode, notes, and visual modes, which keeps the UI consistent as the lab grows.
replay over mutation
Precomputed steps made it much easier to synchronize explanations, metrics, quiz prompts, and scrubber playback without hidden state drifting out of sync.
portfolio framing
Shareable URL state, compare mode, and responsive layouts mattered as much as the algorithm logic because this page needs to teach clearly and still feel polished as a product.
more in this lane
Want a different take on the same problem family? These stay in the same category but change the strategy.
beginner
Bubble Sort
Repeatedly swaps adjacent out-of-order values so larger numbers drift to the end.
beginner
Selection Sort
Selects the minimum value from the unsorted suffix and places it into the next sorted slot.
beginner
Insertion Sort
Builds a sorted prefix by inserting each new value into the right gap.