A comparison sort is a type of sorting algorithm that only reads the list elements through a single abstract comparison operation (often a "less than or equal to" operator) that determines which of two elements should occur first in the final sorted list. The only requirement is that the operator obey two of the properties of a total order:
- if a ≤ b and b ≤ c then a ≤ c (transitivity)
- for all a and b, either a ≤ b or b ≤ a (totalness or trichotomy).
It is possible that both a ≤ b and b ≤ a; in this case either may come first in the sorted list. In a stable sort, the input order determines the sorted order in this case.
A metaphor for thinking about comparison sorts is that someone has a set of unlabelled weights and a balance scale. Their goal is to line up the weights in order by their weight without any information except that obtained by placing two weights on the scale and seeing which one is heavier (or if they weigh the same).
Read more about Comparison Sort: Examples, Performance Limits and Advantages of Different Sorting Techniques, Number of Comparisons Required To Sort A List
Famous quotes containing the words comparison and/or sort:
“It is comparison than makes people miserable.”
—Chinese proverb.
“My father and I were always on the most distant terms when I was a boy—a sort of armed neutrality, so to speak. At irregular intervals this neutrality was broken, and suffering ensued; but I will be candid enough to say that the breaking and the suffering were always divided up with strict impartiality between us—which is to say, my father did the breaking, and I did the suffering.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)