mockingjet / algo

Algorithm Practice in Java

Sorting Algorithms

	inplace?	stable?	best	average	worst	remarks
selection	Y		½ * N^2	½ * N^2	½ * N^2	N exchanges
insertion	Y	Y	N	¼ N 2	½ N^2	use for small N or partially ordered
shell	Y		N logN/log3	?	c N^3/2	tight code; subquadratic
merge		Y	½ N lg N	N lg N	N lg N	N log N guarantee; stable
timsort		Y	N	N lg N	N lg N	improves mergesort when preexisting order
quick	Y		N lg N	2 N ln N	½ N 2	N log N probabilistic guarantee;fastest in practice
3-way quick	Y		N	2 N ln N	½ N 2	improves quicksort when duplicate keys
heap	Y		N lg N	2 N ln N	2 N lg N	N log N guarantee; inplace; poor use of cache
?	Y	Y	N	N lg N	N lg N	holy sorting grail

Sorting Attributes

• Deterministic? (same input has same efficiency)

not for quicksort due to shuffling

• Large Items?

selection sort has fewest exchanges

• Guaranteed Performance?

quicksort's worst case: 1/2 * N^2, which is much slower than average case: N * lgN