Happy tickets benchmark

Submitted by st on Sat, 13/02/2016 - 10:49

Some countries have integer numbers printed on the transport tickets, for example, in ex-USSR. The ticket is "happy" when the sum of the first half of digits equals to the second one. Then you should eat it and make a wish.

Example:

123456 and 111222 are not happy tickets
123123 and 123222 are the happy tickets

Testing

Bit-packed structure (record) in Free Pascal and Delphi

Submitted by st on Sat, 19/12/2015 - 11:58

Here is the code explaining some methods to pack bit accessing logic in your program.

program project1;
 
type
  TRec1 = packed record // Doesn't pack at all
    b1, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16: boolean;
  end;
 
  TRec2 = bitpacked record // Free Pascal specific
    b1, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16: boolean;
  end;
 
  TRecByte = (b1, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16);
  TRecBytes = set of TRecByte;
var
  r1: TRec1;
  r2: TRec2;
  s1: TRecBytes;

Programming

Delphi |
Free Pascal

Sorted map vs hashed map

Submitted by st on Mon, 20/07/2015 - 14:26

In theory, hash map structure should be very fast on retrieving by key operations, close to O(1) like for an array. A sorted map (keys are sorted) should be O(log₂ N) instead. The following test checks the difference.

Common scenario

We will use one tester class per type of tested structure. The keys are string[10] and are generated randomly in prepared array to avoid additional checks whether the key exists or not.