What is computational Computational thinking thinking refers to a way of approaching problems that is particularly useful in computing. It can also be useful for tackling many other kinds of problems What is abstraction Abstraction refers to the process of finding similarities or common aspects between problems and identifying differences and details that don't matter for the task at hand. What are heuristics? strategies for simplifying a problem or for guiding an investigation What is an algorithm? A sequence of steps required to solve a problem What is abstraction? Abstraction refers to the process of finding similarities or common aspects between problems, and identifying differences and details that don't matter for the task at hand What is decomposition? Decomposition involves breaking down a large task into a set of smaller tasks What are two It ways can save in which time,identifying and lead topatterns more elegant can help solutions us to solve problems in computing. In relation toElegance algorithms, refers what to does how desirable 'elegance'the refer algorithm to is. Specifically how fast, and accurate it is. For example if an algorithm could produce a correct answer, extremely quickly, 99% of the time, it would be extremely elegant. Why is abstraction Computers necessary are soin complex, computing? that it is impossible for the average person to understand every single detail of how they work. When can we When use abstraction defining functions when designing programs? Explain howYou functions don't need can be to used knowto exactly achieve how abstraction an argument operates, e.g., print(), as long as you understand how it works What is an algorithm A sequence of steps required to solve a problem Be unambiguous Consist of a finite number of steps Algorithms for Have computers a clear flow must ofmeet control additional from thecriteria beginning thanofnon-computational the algorithm to thecomputer end works, what are they? What is pseudocode? A mix of programming language and normal/everyday language used to describe instructions in a program less formally than using a programming language alone What is the purpose To represent of a computer the instructions program in an in relation algorithm to in ansuch algorithm a way that they can be executed by a computer Best case: When there is the least amount of work What is the difference Worst case: between When there worst-case is the most scenarios amount andofbest-case work scenarios in an algorithm, with respect to the work done? Why do computer This isscientists the optiontend that to requires base estimates the most of time work anddone is therefore by an algorithm the mostonconservative the worst-case scenarios? What does algorithmic Algorithmictime timecomplexity complexitymean? is a measure of how long an algorithm would take to complete, given input n What is the only Timefactor that computer scientists consider when looking at algorithmic complexity? What is meant When by 'Linear the amount complexity' of work done is linearly proportional to the input size n What is meant Theby special Big O notation notation for describing algorithmic time complexity What are equivalence Equivalence classes classes of group algorithms? algorithms that have an equivalent (more or less) complexity. What does 0(n) A linear classsearch, represent? which runs in 0(n) time What does 0(1) An algorithm class represent? that only looks at the first item in a data set What does 0(n^2) A quadratic class algorithmic represent? complexity, one that grows in proportion to the square of the input size. So if n=8 then the output = 64 They allow us to see which algorithms are in the same class They allow us to quantify the difference in complexity Why are equivalence Equivalence classes classes are can so important? prevent computer scientists from wasting time looking for better algorithms that don't exist, as they can often be proven mathematically. Give an example Linearofsearch an algorithm algorithm that belongs to the 0(n) class In relation toThe algorithmic highest order complexity, of 'n' what is considered to be a 'dominant term'. Explain whatProblems is meant that by 'intractable' no algorithm problems can solve in a reasonable amount of time, for example the travelling salesman What is heuristic, A rule in of the thumb non-computer which allows sense? us to produce an approximate, yet usable solution to a problem When are heuristics When one useful? needs a solution to an intractable problem? The accuracy of a solution ma not always be known What are two Some problems heuristics associated may make withassumptions solutions based about on the heuristic original algorithms problems that may not be fair or appropriate. Under what When circumstances the problem are is heuristics fully understood, best applied? and the consequences of any assumptions can be known and preferably quantified. What is a continuous Analog data, signal? in other terms, data that has more than two values (0 and 1), e.g, the amount of numbers between 0 and 1 (infinite) What is a discrete Digitalsignal? data, in other terms, data that has only two values, 1 or 0 (ON/OFF) What does sampling The selecting referof to?a subset of data, from the a larger data set/population What is the 'trade-off' Some information in sampling? is lost, as a digital signal can only form approximations from a continuous signal, for example 4.4 becomes 4 What are theItadvantages is much easier of storing to transport, information store and in digital copyformat? than the analog alternative. How many bits are in a8 byte? What is the largest 1111 1111 value orthat 255can be stored by a byte in binary and decimal? How many characters 256 different total characters can be stored (2^8)in a byte? How many megabytes 1024 (1024are is the there holy in anumber gigabite? in units of storage, only bits and bytes are the exception) a) (2^40) How many bytes b) (2^50) are there in a terabyte (a), and a petabyte (b) Using an example 1000 0001 of a binary, the 1'slabel respectively the most from andleft least to important right are: Most bit important, and least important What is the first 2^0,place or 1 value in a binary number? What does the It'sposition place value of each bit in a byte represent? State two benefits Simplicity, of using can binary be carried numbers out quickly in computers by a computer NOT & What are theAND names of the two logic circuits used for binary addition? What base is used for 16Hexadecimal numbers? (0x) What is the least 16^0,significant or 1 digit in hexadecimal 0b1110 to Hex 1F = ? Give one reason They why provide programmers a way of representing find Hex useful? binary values using fewer digits, in hex only two hex digits are needed to represent one byte as 1111 = 15 What is the difference A half-adder between circuit uses a half-adder only 2 inputs, and a full A and adder B, whereas circuit? a full adder, is more complicated and uses 3 inputs, A,B and C What is meant A collection by the term of character characters, set? that are used for a specific purpose, such as a language. E.g., in English we use the roman character set How many characters 128could the original 7-bit ASCII code represent? How many characters 256can be represented by the 8-bit ASCII What is Unicode? Unicode, or the universal character set, allows for non-roman character sets. What does Unicode t allows allow us to represent us to do? a great variety of characters including those from major languages and many other symbols, such as emoji Which requires Unicode, more storage as it contains spacesignificantly ASCII or Unicode, more characters. and why? What does UTF-8 Unicode-Transformation-Format, stand for, and what is the relevance 8 bit. Theof8the means 8 that it uses 8-bit blocks to represent a character. The UTF-8 method Meaning is backward all encodings compatible in ASCII are withthe ASCII. same What in UTF-8 does this mean? What is the main UTF-8encoding method used on the Internet? UTF-8 is a variable-width The characterencoding set is encoded method, with explain codesthis of different meaning.lengths What is meant Theby unique a code-point binary code in UTF-8 that represents each character Give an example U+0080 of how a UTF-8 code point is written State why ASCII Theyand provide Unicode standard are important ways for computers to represent characters that are readable by other computers.
