Chapter 3 CIS

Protest loop

(While loop) Do iteration loop before you print (after condition)

Order of magnitude

0(n)Set of functions that grow in a linear fashion. Efficiency classification of an algorithm whose work varies as constant times the input(increases)

Polynomial bounded

Algorithm that does work in the order of 0(n^k). Most common programs are this type except Hamilton circuit

Elegance

Algorithmic equivalent of style. Attributes- if correct, ease of understanding, and efficiency. Clever non obvious approach

Approximation algorithms

Algorithms that partially solve or provide sub optimal solutions to intractable problems

Sequential search algorithm

An algorithm that searches for a target value in a random list by checking each list item in term. Check list in order. One at a time. Much check all of list

Space effficiency

Be judged by the amount of info the algorithm must store in the computers memory in order for it to do its job

Karl Fredrick Gauss

Best known for elegant algorithm he created as a schoolchild.

Space efficiently for copy over

Best: all zeros and no extra space. Worse:no zeros, uses n extra spaces.

Worst case

Big input list (sequential search)!Greatest amount of work algorithm does

Best case

Big input list(sequential search algorithm)it is the smallest amount an algorithm does

Ease of understanding

Clarity. Ease of handling is a high desirable characteristic of an algorithm. Ex Pseudocode and flow charts

Time efficiency best case

Copy over; all zeros and checks each value but doesn't copy it

Attributes of interest

Correctness,ease of understanding, elegance, and efficiency

Shuffle left for time efficiency

Count comparisons looking for 0 and movement of values

Copy over algorithm

Create a second

Copy over algorithm

Create a second, initially empty list. Look at each value in the original. If it is non-zero, copy it to the 2nd lisst

Average caase

Depends on likelihood of different scenarios occurance

Post loop

Do iteration after the loop

Algorithms that conflict

Elegance and ease of understanding

Flops

Floating point operations per second

Binary search algorithm

Given a target and an ordered list of values, find the location of the target in the list, if it occurs,by starting in the middle and splitting the range in 2

Order of magnitude of lg n

Grows very slowly

Sequential sort algoritjm

Keeps moving the larger items toward the back of the list

Bubble sort algorithm

Makes multiple passes through the list from front to back, each time. Each time exchanging pairs of interiors that are out of order

Time efficiency worst case

No zeros. Checks each value and copies it

Exponential growi

O(2^n)

Order n^2 thrv

O(n^2)

Sequential search

Operations most important for the task and occurring frequently. Comparison of taget NAME to each game in the list

Program maintenence

Person modifying eiher to correct eerors or to expand its functionality

Benchmarking

Use to prove efficiency. Runs program in many data sets to be sure it's performance faces with in required limits; timing the same algorithm on 2 different machines

Ease of understandig

Useful for checking correctness and program maintenance

Benchmarking

Useful for rating one machine against another and rating how sensitive a profile algorithm with respect to various variations

Shuffle left for specs efficiency

Uses no significant space beyond input

Intractable

Problems with no ply bounded solutions: Hamilton circuit, traveling salesperson, bin packing, and chess

Sorting

Putting a list of values into numeric or alphabetical order. Past repeatedly over the unsorted portion of list. Each pass sect highest remaining value. Move value to end if unsorted values

Short sequential seatch

Requires a sorted list and stops once it passed places where the target could occur

Shuffle left algorithm

Search for 0s left and right. When zeros if found, shift all values to its right ind cell to the left

Best case

Sequential search ;Target found with the first composition

Worse case

Sequential search. Target never found or last value

Average

Sequential search; of each value is equal likely to be searched, work does varies from a 1-n, averages to n/2

Order n^2

Set of functions whose growth is in the order n^2

Worse case

Shuffle left; Everything is zero, movement values; then n - 2 values etc.

Best case

Shuffle left; No terms

Smart bubble sort

Stops when no exchanges occur on a given pass

Analysis of algorithms

Study of the Efficiency of an algorithm. Important part of Computer science

Efficency

Term used to describe an algorithms careful use of time and space resources. In addition to correctness,ease of understanding, and elegance. Extremely desirable attribute of an algorithm

Searching

The task finding a specific value of a list of values; or decisive if it's not there