1 / 19

Data Representation Methods

Data Representation Methods. array --- Chapter 5 linked --- Chapter 6. 0. 1. 2. 3. 4. 5. 6. Linear List Array Representation. use a one-dimensional array element[]. a. b. c. d. e. L = (a, b, c, d, e) Store element i of list in element[i]. e. d. c. b. a.

ckibbe
Download Presentation

Data Representation Methods

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Data Representation Methods array --- Chapter 5 linked --- Chapter 6

  2. 0 1 2 3 4 5 6 Linear List Array Representation use a one-dimensional array element[] a b c d e L = (a, b, c, d, e) Store element i of list in element[i].

  3. e d c b a Right To Left Mapping

  4. a b c d e Mapping That Skips Every Other Position

  5. d e a b c Wrap Around Mapping

  6. a b c d e 0 1 2 3 4 5 6 Representation Used In Text put element i of list in element[i] use a variablelistSizeto record current number of elements listSize = 5

  7. listSize = 5 a b c d e listSize = 6 a g b c d e Insert/Erase An Element insert(1,g)

  8. Data Type Of Array element[] Data type of list elements is unknown. Define element[]to be of template typeT.

  9. Length of Array element[] Don’t know how many elements will be in list. Must pickan initial length and dynamically increase as needed. Use variable arrayLength to store current length of array element[].

  10. a b c d e f Increasing Array Length Length of array element[] is 6. First create a new and larger array T* newArray = new T[15];

  11. a b c d e f a b c d e f Increasing Array Length Now copy elements from old array to new one. copy(element, element + 6, newArray);

  12. element[0] a b c d e f Increasing Array Length Finally, delete old array and rename new array. delete [] element; element = newArray; arrayLength = 15;

  13. template<class T> void changeLength1D(T*& a, int oldLength, int newLength) { if (newLength < 0) throw illegalParameterValue(); T* temp = new T[newLength]; // new array int number = min(oldLength, newLength); // number to copy copy(a, a + number, temp); delete [] a; // deallocate old memory a = temp; }

  14. How Big Should The New Array Be? At least 1 more than current array length. Cost of increasing array length when array is full is Q(old length). Cost of n insert operations done on an initially empty linear list increases by Q(n2).

  15. a b c d e f Space Complexity element[6] newArray = new char[7]; space needed = 2 * newLength – 1 = 2 * maxListSize – 1

  16. a b c d e f a b c d e f Array Doubling Double the array length. newArray = new char[12]; Time for ninserts goes up byQ(n). Space needed =1.5*newLength. Space needed <= 3*maxListSize – 3

  17. Resizing by an additive constant increases the cost ofnadd operations byQ(n2). How Big Should The New Array Be? Resizing by any constant factor new length = c * old length increases the cost of ninserts by Q(n).

  18. How Big Should The New Array Be? Resizing by any constant factor new length = c * old length requires at most (1+c) * (maxListSize -1)space. Resizing by an additive constant crequires at most (maxListSize – 1) + (maxListSize – 1 + c) = 2 * (maxListSize – 1) + c space.

  19. What Does C++ Do? STL class vector … c = 1.5 arrayList of text … c = 2

More Related