1. Class No.32 Data Structures http://ecomputernotes.com

2. Tables and Dictionaries http://ecomputernotes.com

12. Binary Search If ( value == middle element ) value is found else if ( value < middle element ) search left-half of list with the same method else search right-half of list with the same method http://ecomputernotes.com

13. Case 1: val == a[mid] val = 10 low = 0, high = 8 5 7 9 10 13 17 19 1 27 1 2 3 4 5 6 7 0 8 a: low high Binary Search mid mid = (0 + 8) / 2 = 4 10 http://ecomputernotes.com

14. Case 2: val > a[mid] val = 19 low = 0, high = 8 mid = (0 + 8) / 2 = 4 Binary Search -- Example 2 5 7 9 10 1 13 17 19 27 1 2 3 4 5 6 7 0 8 a: mid low high new low new low = mid+1 = 5 13 17 19 27 http://ecomputernotes.com

15. Case 3: val < a[mid] val = 7 low = 0, high = 8 mid = (0 + 8) / 2 = 4 Binary Search -- Example 3 10 13 17 19 5 7 9 1 27 1 2 3 4 5 6 7 0 8 a: mid low high new high new high = mid-1 = 3 5 7 9 1 http://ecomputernotes.com

16. val = 7 Binary Search -- Example 3 (cont) 5 7 9 10 13 17 19 1 27 1 2 3 4 5 6 7 0 8 a: 5 7 9 10 13 17 19 1 27 1 2 3 4 5 6 7 0 8 a: 5 7 9 10 13 17 19 1 27 1 2 3 4 5 6 7 0 8 a:

27. Lecture No.38 Data Structure Dr. Sohail Aslam

28. Skip List: formally 56 64 78  31 34 44  12 23 26 S 0 64  31 34  23 S 1  31  S 2   S 3

30. Skip List: Search Example: search for 78   S 0 S 1 S 2 S 3  31  64  31 34  23 56 64 78  31 34 44  12 23 26

37. Skip List: Implementation   S 0 S 1 S 2 S 3   45 12 23 34   34   23 34

40. Skip Lists with Quad Nodes 56 64 78  31 34 44  12 23 26    31  64  31 34  23 S 0 S 1 S 2 S 3

51. Finding the hash function int hashCode( char* s ) { int i, sum; sum = 0; for(i=0; i < strlen(s); i++ ) sum = sum + s[i]; // ascii value return sum % TABLESIZE; }