Summary of CS 3345 Ch 7 Part 3

00:00:00 - 00:20:00

In this video, the author discusses how to pick a pivot in a quick sort, and how the running time for the algorithm is affected by the choice of pivot. They demonstrate how to move an element in an array using the less-than operator (<), and how to compare two elements to determine which is greater. They also discuss how to swap two elements if they are not equal.

• 00:00:00 The Quick Sort algorithm divides an input array into two parts, and recursively sorts the two parts. The first part is sorted according to the value of the element at the position of the pivot, and the second part is sorted according to the values of the other elements.
• 00:05:00 In this video, the author describes how to pick a pivot in a quick sort. The author warns that choosing the pivot randomly is not a safe way to do it, and recommends the median of three partitioning.
• 00:10:00 In this video, the author demonstrates how to move an element in an array using the less-than operator (<), and how to compare two elements to determine which is greater. They also discuss how to swap two elements if they are not equal.
• 00:15:00 In the quick sort algorithm, the pivot is always placed in the middle of the array, and the smaller and greater sub-arrays are always equal in size. The quick sort algorithm has a running time of "tita" if the pivot is the smallest element all the time, and "tita" plus "cn" if the pivot is not the smallest element all the time.
• 00:20:00 This video discusses how the running time for the quick sort is equal to the 2 t n divided by 2 plus c n c n .