How Merge Sort Works
- Waiting
- Being compared
- Just moved
- In final position
1/50
Merge sort, 12 values in random order.
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More options
Starting order
Two to 48 numbers, used in the order you type them.
Merge Sort
- 1
width = 1 - 2
while width < n: - 3
for lo in 0..n step 2*width: - 4
mid = lo + width - 5
hi = lo + 2*width - 6
// merge a[lo..mid) and a[mid..hi) - 7
take the smaller head each time - 8
width *= 2
How the Seven Compare
| Algorithm | Best | Average | Worst | Extra memory | Stable |
|---|---|---|---|---|---|
| Bubble | O(n) | O(n²) | O(n²) | O(1) | Yes |
| Insertion | O(n) | O(n²) | O(n²) | O(1) | Yes |
| Selection | O(n²) | O(n²) | O(n²) | O(1) | No |
| Shell | O(n log n) | O(n√n) | O(n²) | O(1) | No |
| Merge | O(n log n) | O(n log n) | O(n log n) | O(n) | Yes |
| Quick | O(n log n) | O(n log n) | O(n²) | O(log n) | No |
| Heap | O(n log n) | O(n log n) | O(n log n) | O(1) | No |
Scroll the table sideways for the rest of the columns.
Stable means equal values keep their original order.