Quicksort Z Merge Sort Z T(N) = Θ(N Lg(N)) Z Not In-Place CSE 680 Z Selection Sort (From Homework) Prof
Sorting Review z Insertion Sort Introduction to Algorithms z T(n) = Θ(n2) z In-place Quicksort z Merge Sort z T(n) = Θ(n lg(n)) z Not in-place CSE 680 z Selection Sort (from homework) Prof. Roger Crawfis z T(n) = Θ(n2) z In-place Seems pretty good. z Heap Sort Can we do better? z T(n) = Θ(n lg(n)) z In-place Sorting Comppgarison Sorting z Assumptions z Given a set of n values, there can be n! 1. No knowledge of the keys or numbers we permutations of these values. are sorting on. z So if we look at the behavior of the 2. Each key supports a comparison interface sorting algorithm over all possible n! or operator. inputs we can determine the worst-case 3. Sorting entire records, as opposed to complexity of the algorithm. numbers,,p is an implementation detail. 4. Each key is unique (just for convenience). Comparison Sorting Decision Tree Decision Tree Model z Decision tree model ≤ 1:2 > z Full binary tree 2:3 1:3 z A full binary tree (sometimes proper binary tree or 2- ≤≤> > tree) is a tree in which every node other than the leaves has two c hildren <1,2,3> ≤ 1:3 >><2,1,3> ≤ 2:3 z Internal node represents a comparison. z Ignore control, movement, and all other operations, just <1,3,2> <3,1,2> <2,3,1> <3,2,1> see comparison z Each leaf represents one possible result (a permutation of the elements in sorted order).
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