1 / 10

Lecture 1

Lecture 1. Array Record Sequential Search Binary Search Bubble Sort Recursion Complexity. Topics. Array. An array is a sequence of elements. All the elements of an array must be of the same type (e.g. integer). Each elements can be selected by specifying its position. int list[10].

evita
Télécharger la présentation

Lecture 1

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. Lecture 1 • Array • Record • Sequential Search • Binary Search • Bubble Sort • Recursion • Complexity Topics Data Structure and Algorithm

  2. Array • An array is a sequence of elements. • All the elements of an array must be of the same type (e.g. integer). • Each elements can be selected by specifying its position. int list[10] index char city[5] index Data Structure and Algorithm

  3. Record • A record/structure is a collection of one or more variables, possibly of different types. • An array is a sequence of elements all having the same type and size, whereas a record or structure is a sequence of elements having different types and sizes. • Each element of a record is its member. Employee: Record name:char[20] address:char[50] salary: real struct employee{ char name[20]; char address[50]; float salary; }; Fig: C Convention Data Structure and Algorithm

  4. Sequential Search • [ Find the location where list array keeps the value of k ] • sequential_search(k) returns integer • Begin • i = 0 • while i<array_size and list[i] <>k do • i = i+1 • if i<array_size then • return i • else • return -1 • End Data Structure and Algorithm

  5. “C” implementation of Sequential Search • #include <stdio.h> • int list[10] = {5,6,1,3,4,1,7,2,0,3}; • int array_size = 10; • int sequential_search(int k){ • int i = 0; • while ( (i<array_size) && ( list[i] != k) ) • i++; • if (i<array_size) • return i; • else • return -1; • } • void main(){ • int pos = sequential_search(2); • printf(“The position is:%d”,pos); • } Data Structure and Algorithm

  6. Binary Search • [ Find the location where sorted table array keeps the value of k ] • binary_search(k): returns integer • BEGIN • l = 0 • h = array_size • found = 0; • while l<h and found = 0 do • m= (l+h)/2 //find the middle element • xm = table[m] • case • xm<k: l = m+1 • xm>k: h = m-1 • xm=k: found = 1 • if found then return m • else return -1 • END Data Structure and Algorithm

  7. “C” Implementation of Binary Search • #include <stdio.h> • int table[10] = {1,5,8,12,15,20,34,40,55,67}; • int array_size = 10; • int binary_search(int k){ • int l =0; • int h = array_size; • int found =0,m,xm; • while ( (l<h) && (found == 0) ){ • m = (l+h)/2; • xm = table[m]; • if (xm<k) l = m+1; • else if (xm>k) h = m-1; • else found = 1; • } • if (found) return m; • else return -1; • } • void main(){ • int pos = binary_search(20); • printf("The position is:%d",pos); • } Data Structure and Algorithm

  8. Recursive Binary Search • [ Find the location where sorted table array keeps the value of k ] • binary_search(l,h,k) • BEGIN • if l>h • index = -1 • else • m= (l+h)/2 //find the middle element • xm = table[m] • case • xm<k: binary_search(m+1,h) • xm>k: binary_search(l,m-1) • xm=k: index=m • END Data Structure and Algorithm

  9. Bubble Sort • For i=0 to n-2 do • BEGIN • For j = i+1 to n-1 do • BEGIN • if list[i] > x[j] then • swap list[i] and list[j] • END • END Data Structure and Algorithm

  10. Complexity Generally the complexity of an algorithm is measured by the two factors: • Time complexity • Space complexity • Sequential search : O(n) • Binary search: O(log2n) • Bubble sort: O(n2) Data Structure and Algorithm

More Related