quartz/content/notes/heapsort.md

title	aliases	tags
heaps-and-heapsort		cosc201

3 Heap Sort

In place and ϴ(n lg n)

• start with array
• using itself as a heap, add the elements one at a time until all been added
• Then remove them one at a time - the largest elements gets removed first and the place where is needs to be put gets freed from the map

4 Heap sort vs Merge sort

heap --> in place, ϴ(n lg n) merge --> not in place, Ο(n lg n)

Merge is preferred because

• MS can take advantage of partially sorted data (hence ϴ() vs Ο())
• MS memory accesses are good fast
• overwrites allow for optimizations that swaps do not

extra memory cost of merge sort is negligible

∴ Merge sort is faster