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Feb 96 Challenge
Volume Number:12
Issue Number:2
Column Tag:Programmer’s Challenge

Programmer’s Challenge

By Bob Boonstra, Westford, Massachusetts

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

Intersecting Rectangles

The Challenge this month is to write a routine that will accept a list of rectangles and calculate a result based on the intersections of those rectangles. Specifically, your code will return a list of non-overlapping rectangles that contain all points enclosed by an odd (or even) number of the input rectangles. The prototype for the code you should write is:

void RectangleIntersections(
 const Rect inputRects[], /* list if input rectangles */
 const long numRectsIn,   /* number of inputRects */
 Rect outputRects[], /* preallocated storage for output */
 long *numRectsOut,/* number of outputRects returned */
 const Boolean oddParity  /* see text for explanation */
);

The parameter oddParity indicates whether you are to return rectangles containing points enclosed by an odd number of the numRectsIn inputRects rectangles (oddParity==true) or by an even (nonzero) number of rectangles (oddParity==false). Sufficient storage for the output will be preallocated for you and pointed to by outputRects.

As an example, if you were given these inputRects:

 {0,10,20,30}, {5,15,20,30}

and oddParity were true, you might return the following list of outputRects:

 {0,10,5,15}, {0,15,5,30}, {5,10,15,20}

It would also be correct to return a result that combined the first of these rectangles with either of the other two. If oddParity were false, you would return the following list for the example input:

 {5,15,20,30}

The outputRects must be non-empty and non-overlapping. In the example, it would be incorrect to return the following for the odd parity case:

 {0,10,5,30} {0,10,20,15}

The outputRects you generate must also be maximal, in the sense that each edge of each of the outputRects should pass through a vertex of one of the inputRects. That is, for example, I don’t want you to return a 1¥1 rectangle representing each point enclosed in the desired number of inputRects. Before returning, set *numRectsOut to indicate the number of outputRects you generated.

If you need auxiliary storage, you may allocate any reasonable amount within your code using toolbox routines or malloc, but you must deallocate that storage before returning. (No memory leaks! - I’ll be calling your code many times.)

This native PowerPC Challenge will be scored using the latest Metrowerks compiler, with the winner determined by execution time. If you have any questions, or would like some test data for your code, please send me e-mail at one of the Programmer’s Challenge addresses, or directly to bob_boonstra@mactech.com. Test data will also be sent to the Programmer’s Challenge mailing list, which you can join by sending a message to autoshare@mactech.com with the SUBJECT line “sub challenge YourName”, substituting your real name for YourName.

Two Months Ago Winner

Eight of the 13 solutions submitted for the Find Again And Again Challenge worked correctly. Congratulations to Gustav Larsson (Mountain View, CA) for submitting an entry that was significantly faster than the others. The problem was to write a text search engine optimized to operate repeatedly on the same block of text. A variety of optimization techniques were represented in the solutions, a couple of which are highlighted in the table of results below. Several people optimized for the case where the same word was repeatedly searched for. Some of my tests included this case, and those results are in the columns headed “repeat.” The “random” columns shows results for tests that searched for random occurrences of random words. Each of the tests were run under conditions where only 64KB of auxiliary storage was available, and where much more memory was available. These conditions were weighted 20% and 80% respectively in calculating the total time, since the problem statement promised that ample memory would usually be provided. You can see that Gustav’s solution performed reasonably well when memory was scarce, and very well when memory was plentiful.

Gustav’s solution hashes as many words of the input text as possible in the initialization routine. He uses the Boyer-Moore-Horspool algorithm to find words in any text that was not parsed during initialization. Other features of the approach are described in the well-commented code.

Here are the times and code sizes for entries that passed by tests. Numbers in parentheses after a person’s name indicate that person’s cumulative point total for all previous Challenges, not including this one.

64K Memory >>64K Memory code

Name repeat random repeat random time size

Gustav Larsson (67) 1814 3773 62 111 1255 3584

Tom Saxton 46 16400 197 459 3814 2000

Xan Gregg (81) 27 2907 1316 2835 3907 1664

Kevin Cutts (46) 1760 3234 1760 2809 4654 1600

Joseph Ku 8856 14570 121 509 5189 1584

David Cary 60 22665 499 1000 5745 2124

Eric Lengyel (40) 34 10221 29 4697 5831 1188

Ernst Munter (110) 2036 2053 2287 4603 6330 2976

Top Contestants of All time

Here are the Top Contestants for the Programmer’s Challenges to date, including everyone who has accumulated more than 20 points. The numbers below include points awarded for this month’s entrants.

Rank Name Points Rank Name Points

1. [Name deleted] 176 11. Mallett, Jeff 44

2. Munter, Ernst 110 12. Kasparian, Raffi 42

3. Gregg, Xan 88 13. Vineyard, Jeremy 42

4. Larsson, Gustav 87 14. Lengyel, Eric 40

5. Karsh, Bill 80 15. Darrah, Dave 31

6. Stenger, Allen 65 16. Landry, Larry 29

7. Riha, Stepan 51 17. Elwertowski, Tom 24

8. Cutts, Kevin 50 18. Lee, Johnny 22

9. Goebel, James 49 19. Noll, Robert 22

10. Nepsund, Ronald 47

There are three ways to earn points: (1) scoring in the top 5 of any Challenge, (2) being the first person to find a bug in a published winning solution or, (3) being the first person to suggest a Challenge that I use. The points you can win are:

1st place 20 points 5th place 2 points

2nd place 10 points finding bug 2 points

3rd place 7 points suggesting Challenge 2 points

4th place 4 points

Here is Gustav’s winning solution:

Find Again and Again

Copyright © 1995 Gustav Larsson

Constants & Types
#define ALPHABET_SIZE 256
#define ALLOC_SIZE(n) ((n+3) & -4L) /* next multiple of 4 */
#define HASH_BUCKETS 1024           /* must be power of 2 */
#define HASH_MASK (HASH_BUCKETS - 1)
#define NO_NULL_CHAR 'A'
#define NULL 0

typedef unsigned char  uchar;
typedef unsigned short ushort;
typedef unsigned long  ulong;

typedef struct Word Word;
typedef struct Occurrence Occurrence;
typedef struct Private Private;

/* 
  A block of occurrence positions.  We pack in as many occurrences as possible into 
  a single block, from 3 to 6 depending on textLength.

  The first entry in the block is always used.  The remaining entries are in use if they 
  are not zero.  These facts are used several places to simplify the code.
*/
struct Occurrence {
  Occurrence *next;
  union {
    ushort pos2[6];   /* 2 bytes/occurrence */
    struct {
      ushort lo[4];
      uchar  hi[4];
    } pos3;           /* 3 bytes/occurrence */
    long pos4[3];     /* 4 bytes/occurrence */
  } p;
};

/*
  There is one Word struct for each distinct word.  The word’s length is stored in the 
  top eight bits of the hash value.  There’s no need to store the characters in the word 
  since we can just look at the first occurrence (first entry in Word.first).
*/
struct Word {
  Word        *next;
  ulong       hash;
  Occurrence  *last;
  Occurrence  first;
};

/*
  The structure of our private storage.  The hashCodes[] array serves two purposes: it 
  distinguishes alphanumeric from non-alphanumeric characters, and it provides a 
  non-zero hash code for each alphanumeric character.  The endParsedText field will 
  be -1 if there was enough private memory to parse all the text.  Otherwise, it points to 
  the start of the unparsed text.  nullChar is used by the BMH_Search() function when 
  we must search unparsed text for an occurrence.
*/
struct Private {
  ulong hashCodes [ ALPHABET_SIZE ];
  Word  *hashTable [ HASH_BUCKETS ];
  long  endParsedText;  /* start of parsed text */
  long  posBytes;       /* POS_x_BYTES, below */
  char  nullChar;       /* char not appearing in the text */
  long  heap;           /* start of private heap  */
};

Macros
/*
  These macros simplify access to the occurrence positions stored in an Occurrence 
  struct.  Posbytes is a macro argument that is usually set to private->posBytes.  
  However, you can also use a constant for posbytes, which lets the compiler choose 
  the right case at compile time, producing smaller and faster code.
*/
#define POS_2_BYTES 1   /* word position fits in 2 bytes */
#define POS_3_BYTES 0   /* fits in 3 bytes; usual case */
#define POS_4_BYTES 2   /* fits in 4 bytes */

#define GET_POS(pos,occur,index,posbytes)           \
  {                                                 \
    if ( (posbytes) == POS_3_BYTES )                \
      pos = ((long)(occur)->p.pos3.hi[index] << 16) \
          + (occur)->p.pos3.lo[index];              \
    else if ( (posbytes) == POS_2_BYTES )           \
      pos = (occur)->p.pos2[index];                 \
    else                                            \
      pos = (occur)->p.pos4[index];                 \
  }

#define SET_POS(pos,occur,index,posbytes)       \
  {                                             \
    if ( (posbytes) == POS_3_BYTES )            \
    {                                           \
      (occur)->p.pos3.hi[index] = (pos) >> 16;  \
      (occur)->p.pos3.lo[index] = (pos);        \
    }                                           \
    else if ( (posbytes) == POS_2_BYTES )       \
      (occur)->p.pos2[index] = pos;             \
    else                                        \
      (occur)->p.pos4[index] = pos;             \
  }

InitFind
void InitFind (
  char *textToSearch,
  long textLength,
  void *privateStorage,
  long storageSize
)
{
  Private *private = privateStorage;

  private->endParsedText =
    InitFindBody(
        (uchar *)textToSearch,
        textLength,
        privateStorage,
        (uchar *)privateStorage + storageSize
    );

  if ( private->endParsedText != -1 )
    private->nullChar =
      PickNullChar(
            private,
            (uchar *)textToSearch + private->endParsedText,
            (uchar *)textToSearch + textLength );
  else
    private->nullChar = NO_NULL_CHAR;
}

InitFindBody
/*
  This function does most of the work for InitFind().  The arguments have been recast 
  into a more useful form; uchar and ulong are used a lot so that we don’t have to 
  worry about the sign, especially when indexing private->hashCodes[].

  The return value is the character position when the unparsed text begins (if we run 
  out of private storage), or -1 if all the text was parsed.
*/
static long InitFindBody (
  uchar   *textToSearch,
  long    textLength,
  Private *private,
  uchar   *endPrivateStorage
)
{
  uchar       *alloc, *textPos, *textEnd, *wordStart;
  long        wordLength;
  ulong       hash, code;
  Word        *word;
  Occurrence  *occur;

/*
  Init table of hash codes.  The remaining entries are guaranteed to be initialized to 
  zero.  The hash codes were chosen so that any two codes differ by at least five bits.
  */
  {
    ulong *table = private->hashCodes;  /* reduces typing */

    table['0'] = 0xFFC0;  table['5'] = 0xF492;
    table['1'] = 0xFE07;  table['6'] = 0xF31E;
    table['2'] = 0xF98B;  table['7'] = 0xF2D9;
    table['3'] = 0xF84C;  table['8'] = 0xCF96;
    table['4'] = 0xF555;  table['9'] = 0xCE51;

    table['A'] = 0xC9DD;  table['N'] = 0xA245;
    table['B'] = 0xC81A;  table['O'] = 0x9F0A;
    table['C'] = 0xC503;  table['P'] = 0x9ECD;
    table['D'] = 0xC4C4;  table['Q'] = 0x9941;
    table['E'] = 0xC348;  table['R'] = 0x9886;
    table['F'] = 0xC28F;  table['S'] = 0x959F;
    table['G'] = 0xAF5C;  table['T'] = 0x9458;
    table['H'] = 0xAE9B;  table['U'] = 0x93D4;
    table['I'] = 0xA917;  table['V'] = 0x9213;
    table['J'] = 0xA8D0;  table['W'] = 0x6DD3;
    table['K'] = 0xA5C9;  table['X'] = 0x6C14;
    table['L'] = 0xA40E;  table['Y'] = 0x6B98;
    table['M'] = 0xA382;  table['Z'] = 0x6A5F;

    table['a'] = 0x6746;  table['n'] = 0x3C88;
    table['b'] = 0x6681;  table['o'] = 0x3B04;
    table['c'] = 0x610D;  table['p'] = 0x3AC3;
    table['d'] = 0x60CA;  table['q'] = 0x37DA;
    table['e'] = 0x5D85;  table['r'] = 0x361D;
    table['f'] = 0x5C42;  table['s'] = 0x3191;
    table['g'] = 0x5BCE;  table['t'] = 0x3056;
    table['h'] = 0x5A09;  table['u'] = 0x0D19;
    table['i'] = 0x5710;  table['v'] = 0x0CDE;
    table['j'] = 0x56D7;  table['w'] = 0x0B52;
    table['k'] = 0x515B;  table['x'] = 0x0A95;
    table['l'] = 0x509C;  table['y'] = 0x078C;
    table['m'] = 0x3D4F;  table['z'] = 0x064B;
  }

  /*  Determine the number of bytes needed to store each occurrence position. */
  if ( textLength <= 0x10000L )
    private->posBytes = POS_2_BYTES;
  else if ( textLength <= 0x1000000L )
    private->posBytes = POS_3_BYTES;
  else
    private->posBytes = POS_4_BYTES;

  /* Set up variables to handle allocation of private storage. */
  alloc = (uchar *)&private->heap;

  /* Parse the text */
  textPos = textToSearch;
  textEnd = textPos + textLength;

  while ( textPos != textEnd )
  {
    /* Search for start of word */
    while ( private->hashCodes[*textPos] == 0 )
    {
      textPos++;
      if ( textPos == textEnd )
        return -1;  /* parse all text */
    }
    wordStart = textPos;

    /* Search for end of word; generate hash value too */
    hash = 0;
    while ( textPos != textEnd &&
            (code = private->hashCodes[ *textPos ]) != 0 )
    {
      hash = (hash << 1) ^ code;
      textPos++;
    }
    wordLength = textPos - wordStart;
    hash = (hash & 0xFFFFFF) | (wordLength << 24);

    /*
      Record the occurrence.  First we see if a Word struct exists for this word and 
      whether we need to allocate a new Occurrence struct.
    */
    word = LookupWord(
                private,
                (char *)textToSearch,
                (char *)wordStart,
                wordLength,
                hash );
    if ( word )
    {
      long allocateNewBlock, blockSize, i, pos;

      /*
        This word has occurred before, so it already has a Word struct.  See if there’s 
        room in the last Occurrence block for another entry.  Remember that entry #0 in 
        the Occurrence block is always in use, so we can start checking at entry #1 for a 
        non-zero entry.
      */
      occur = word->last;
      allocateNewBlock = TRUE;
      switch ( private->posBytes )
      {
        case POS_2_BYTES:  blockSize = 6; break;
        case POS_3_BYTES:  blockSize = 4; break;
        case POS_4_BYTES:  blockSize = 3; break;
      }

      for ( i = 1; i < blockSize; i++ )
      {
        GET_POS( pos, occur, i, private->posBytes )
        if ( pos == 0 )
        {
          SET_POS( wordStart - textToSearch, occur, i,
                   private->posBytes )
          allocateNewBlock = FALSE;
          break;
        }
      }

      if ( allocateNewBlock )
      {
        /* Block is full.  Allocate new Occurrence block */
        occur = (Occurrence *) alloc;
        alloc += ALLOC_SIZE( sizeof(Occurrence) );
        if ( alloc >= endPrivateStorage )
          return wordStart-textToSearch; /* out of memory */

        /* Init the new struct and link it to the end of the occurence list. */
        SET_POS( wordStart - textToSearch, occur, 0,
                 private->posBytes )
        word->last->next = occur;
        word->last = occur;
      }
    }
    else
    {
      long i;

/* This is a new word.  Allocate a new Word struct, which contains an Occurrence 
    struct too.  */
      word = (Word *) alloc;
      alloc += ALLOC_SIZE( sizeof(Word) );
      if ( alloc >= endPrivateStorage )
        return wordStart-textToSearch ;  /* out of memory */

      /*  Link it to the start of the Word list, coming off the hash table. */
      word->next = private->hashTable[ hash & HASH_MASK ];
      private->hashTable[ hash & HASH_MASK ] = word;

      /* Init the Word struct */
      word->hash = hash;
      word->last = &word->first;

      /* Init the Occurrence struct */
      SET_POS( wordStart - textToSearch, &word->first, 0,
               private->posBytes )
    }
  }

  /* Finished parsing text */
  return -1;
}

FindWordOccurrence
long FindWordOccurrence (
  char *wordToFind,
  long wordLength,
  long occurrenceToFind,
  char *textToSearch,
  long textLength,
  void *privateStorage,
  long storageSize
)
{
  Private *private = privateStorage;
  Word  *word;
  ulong hash;

  /* Make occurenceToFind zero-based */
  occurrenceToFind--;

  /* Generate hash value for word to find */
  hash = 0;
  {
    long remain = wordLength;
    uchar *p = (uchar *) wordToFind;
    while ( remain > 0 )
    {
      hash = (hash << 1) ^ private->hashCodes[*p++];
      remain--;
    }
    hash = (hash & 0xFFFFFF) | (wordLength << 24);
  }

  /* Look for word/occurrence in hash table */
  word = LookupWord( private, textToSearch, wordToFind,
                     wordLength, hash );
  if ( word )
  {
    Occurrence *occur = &word->first;
    long blockSize, pos, i;

    /* Word exists in hash table, so go down the occurrence list.  */
    switch ( private->posBytes )
    {
      case POS_2_BYTES: blockSize = 6;  break;
      case POS_3_BYTES: blockSize = 4;  break;
      case POS_4_BYTES: blockSize = 3;  break;
    }

    while ( occur && occurrenceToFind >= blockSize )
    {
      occurrenceToFind -= blockSize;
      occur = occur->next;
    }

    if ( occur )
    {
      GET_POS( pos, occur, occurrenceToFind,
               private->posBytes )
      if ( occurrenceToFind == 0 || pos != 0 )
        return pos;
      occurrenceToFind -= blockSize;
    }

    occur = word->last;
    for ( i = 0; i < blockSize; i++ )
    {
      GET_POS( pos, occur, i, private->posBytes )
      if ( pos == 0 )
        occurrenceToFind++;
    }
  }

  /* Not in parsed text, so check the unparsed text */
  if ( private->endParsedText != -1 )
  {
    char *p;
    if ( wordLength > 3 )
      p = BMH_Search(
              private->hashCodes,
              wordToFind,
              wordLength,
              occurrenceToFind,
              textToSearch + private->endParsedText,
              textToSearch + textLength,
              private->nullChar );
    else
      p = SimpleSearch(
              private->hashCodes,
              wordToFind,
              wordLength,
              occurrenceToFind,
              textToSearch + private->endParsedText,
              textToSearch + textLength );
    if (p)
      return (p - textToSearch);
  }

  /* Not found */
  return -1;
}

LookupWord 
/* Look up a word in the hash table */
static Word *LookupWord (
  Private *private,
  char    *textToSearch,
  char    *wordText,
  long    wordLength,
  ulong   hash
)
{
  Word *word = private->hashTable[ hash & HASH_MASK ];
  while ( word )
  {
    if ( word->hash == hash )
    {
      char *w1, *w2;
      long pos, remain = wordLength;

      /*
        The hash values match, so compare characters to make sure it’s the right word.  
        We already know the word length is correct since the length is contained
        in the upper eight bits of the hash value.
      */
      GET_POS( pos, &word->first, 0, private->posBytes )
      w1 = textToSearch + pos;
      w2 = wordText;
      while ( remain-- > 0 && *w1++ == *w2++ )
        ;
      if ( remain == -1 )
        return word;
    }
    word = word->next;
  }
  return NULL;
}

PickNullChar 
/*
  Find a character that doesn’t appear anywhere in the unparsed text.  BMH_Search() is 
  faster if such a character can be found.
*/
static char PickNullChar (
  Private *private,
  uchar   *textStart,
  uchar   *textEnd
)
{
  long i;
  uchar *p, occurs[ ALPHABET_SIZE ];

  for ( i = 0; i < ALPHABET_SIZE; i++ )
    occurs[i] = FALSE;

  for ( p = textStart; p < textEnd; p++ )
    occurs[*p] = TRUE;

  for ( i = 0; i < ALPHABET_SIZE; i++ )
    if ( occurs[i] == FALSE && private->hashCodes[i] == 0 )
      return i;

  return NO_NULL_CHAR;
}

BMH_Search
/*
  Search the unparsed text using the Boyer-Moore-Horspool algorithm.  Ideally a null 
  character is supplied (one that appears in neither the search string nor the text being 
  searched).  This allows the inner loop to be faster.
*/
static char *BMH_Search (
  ulong *hashCodes,       /* private->hashCodes     */
  char  *wordToFind,
  long  wordLength,
  long  occurrenceToFind, /* 0 is first occurrence  */
  char  *textStart,       /* start of unparsed text */
  char  *textEnd,         /* end of unparsed text   */
  char  nullChar          /* private->nullChar      */
)
{
  long  i;
  char  *text, *wordEnd;
  char  word[256];
  long  offset[ ALPHABET_SIZE ];

  /*
    Copy the search string to a private buffer, where
    the first character is the null character.
  */
  word[0] = nullChar;
  for ( i = 0; i < wordLength; i++ )
    word[i+1] = wordToFind[i];

  /* Set up the offset[] lookup table */
  for ( i = 0; i < ALPHABET_SIZE; i++ )
    offset[i] = wordLength;

  for ( i = 1; i < wordLength; i++ )
    offset[ word[i] ] = wordLength - i;

  /* Let the search begin... */
  wordEnd = word + wordLength;
  text = textStart + wordLength - 1;

  if ( nullChar == NO_NULL_CHAR )
  {
    /* No null character, so use a slower inner loop */
    while ( text < textEnd )
    {
      long i;
      char *p, *q;
      for ( i = wordLength, p = wordEnd, q = text;
            i > 0 && *p == *q;
            i--, p--, q-- )
        ;
/*If i == 0, we have found the search string.  Now we make sure that it is delimited.*/
      if ( i == 0 && hashCodes[*q] == 0 &&
           (text+1 == textEnd || hashCodes[text[1]] == 0) )
      {
        if ( occurrenceToFind == 0 )
          return q+1;
        occurrenceToFind--;
      }

      text += offset[*text];
    }
  }
  else
  {
    /* There is a null character (usual case), 
        so we can use a faster and simpler inner loop. */
    while ( text < textEnd )
    {
      char *p, *q;
      for ( p = wordEnd, q = text; *p == *q; p--, q-- )
        ;
      if ( p == word && hashCodes[*q] == 0 &&
           (text+1 == textEnd || hashCodes[text[1]] == 0) )
      {
        if ( occurrenceToFind == 0 )
          return q+1;
        occurrenceToFind--;
      }
      text += offset[*text];
    }
  }
  return NULL;
}

SimpleSearch
/*
  Search the unparsed text using a simple search algorithm.  Note that wordLength 
  must be 1, 2, or 3.  This algorithm runs faster than BMH_Search() for small search 
  strings.
*/
static char *SimpleSearch(
  ulong *hashCodes,       /* private->hashCodes      */
  char  *wordToFind,
  long  wordLength,       /* 1..3                    */
  long  occurrenceToFind, /* 0 is 1st occurrence     */
  char  *textStart,       /* start of unparsed text  */
  char  *textEnd          /* end of all text         */
)
{
  char *text, first;

  first = wordToFind[0];
  text = textStart;

  if ( wordLength == 1 )
  {
    while ( text < textEnd )
    {
      while ( text < textEnd && *text != first )
        text++;
      if ( hashCodes[*(text-1)] == 0 &&
           hashCodes[text[wordLength]] == 0 )
      {
        if ( occurrenceToFind == 0 )
          return text;
        occurrenceToFind--;
      }
    text++;
    }
  }
  else if ( wordLength == 2 )
  {
    while ( text < textEnd )
    {
      while ( text < textEnd && *text != first )
        text++;
      if ( text[1] == wordToFind[1] &&
           hashCodes[*(text-1)] == 0 &&
           hashCodes[text[wordLength]] == 0 )
      {
        if ( occurrenceToFind == 0 )
          return text;
        occurrenceToFind--;
      }
    text++;
    }
  }
  else /* wordLength == 3 */
  {
    while ( text < textEnd )
    {
      while ( text < textEnd && *text != first )
        text++;
      if ( text[1] == wordToFind[1] &&
           text[2] == wordToFind[2] &&
           hashCodes[*(text-1)] == 0 &&
           hashCodes[text[wordLength]] == 0 )
      {
        if ( occurrenceToFind == 0 )
          return text;
        occurrenceToFind--;
      }
    text++;
    }
  }
  return NULL;
}

 

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VirtualBox is a family of powerful x86 virtualization products for enterprise as well as home use. Not only is VirtualBox an extremely feature rich, high performance product for enterprise customers... Read more
BetterTouchTool 3.149 - Customize multi-...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom)... Read more
Dropbox 77.4.131 - Cloud backup and sync...
Dropbox is an application that creates a special Finder folder that automatically syncs online and between your computers. It allows you to both backup files and keeps them up-to-date between systems... Read more
MainStage 3 3.4.3 - Live performance too...
Apple MainStage makes it easy to bring to the stage all the same instruments and effects that you love in your recording. Everything from the Sound Library and Smart Controls you're familiar with... Read more
Paperless 3.0.6 - $69.95
Paperless is a digital documents manager. Remember when everyone talked about how we would soon be a paperless society? Now it seems like we use paper more than ever. Let's face it - we need and we... Read more
TextMate 2.0.rc.29 - Code/markup editor...
TextMate is a versatile plain text editor with a unique and innovative feature set which caused it to win an Apple Design Award for Best Mac OS X Developer Tool in August 2006 A rapidly growing... Read more
Notability 4.0.4 - Note-taking and annot...
Notability is a powerful note-taker to annotate documents, sketch ideas, record lectures, take notes and more. It combines, typing, handwriting, audio recording, and photos so you can create notes... Read more
CleanMyMac X 4.4.4 - Delete files that w...
CleanMyMac makes space for the things you love. Sporting a range of ingenious new features, CleanMyMac lets you safely and intelligently scan and clean your entire system, delete large, unused files... Read more
Geekbench 4.4.0 - Measure processor and...
Geekbench provides a comprehensive set of benchmarks engineered to quickly and accurately measure processor and memory performance. Designed to make benchmarks easy to run and easy to understand,... Read more

Latest Forum Discussions

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TEPPEN guide - Tips and tricks for new p...
TEPPEN is a wild game that nobody asked for, but I’m sure glad it exists. Who would’ve thought that a CCG featuring Capcom characters could be so cool and weird? In case you’re not completely sure what TEPPEN is, make sure to check out our review... | Read more »
Dr. Mario World guide - Other games that...
We now live in a post-Dr. Mario World world, and I gotta say, things don’t feel too different. Nintendo continues to squirt out bad games on phones, causing all but the most stalwart fans of mobile games to question why they even bother... | Read more »
Strategy RPG Brown Dust introduces its b...
Epic turn-based RPG Brown Dust is set to turn 500 days old next week, and to celebrate, Neowiz has just unveiled its biggest and most exciting update yet, offering a host of new rewards, increased gacha rates, and a brand new feature that will... | Read more »
Dr. Mario World is yet another disappoin...
As soon as I booted up Dr. Mario World, I knew I wasn’t going to have fun with it. Nintendo’s record on phones thus far has been pretty spotty, with things trending downward as of late. [Read more] | Read more »
Retro Space Shooter P.3 is now available...
Shoot-em-ups tend to be a dime a dozen on the App Store, but every so often you come across one gem that aims to shake up the genre in a unique way. Developer Devjgame’s P.3 is the latest game seeking to do so this, working as a love letter to the... | Read more »
Void Tyrant guide - Guildins guide
I’ve still been putting a lot of time into Void Tyrant since it officially released last week, and it’s surprising how much stuff there is to uncover in such a simple-looking game. Just toray, I finished spending my Guildins on all available... | Read more »
Tactical RPG Brown Dust celebrates the s...
Neowiz is set to celebrate the summer by launching a 2-month long festival in its smash-hit RPG Brown Dust. The event kicks off today, and it’s divided into 4 parts, each of which will last two weeks. Brown Dust is all about collecting, upgrading,... | Read more »
Flappy Royale is an incredibly clever ta...
I spent the better part of my weekend playing Flappy Royale. I didn’t necessarily want to. I just felt like I had to. It’s a hypnotic experience that’s way too easy to just keep playing. | Read more »
Void Tyrant guide - General tips and tri...
Void Tyrant is a card-based dungeon-crawler that doesn’t fit in the mold of other games in the genre. Between the Blackjack-style combat and strange gear system alone, you’re left to your own devices to figure out how best to use everything to your... | Read more »
Webzen’s latest RPG First Hero is offici...
You might be busy sending your hulking Dark Knight into the midst of battle in Webzen’s other recent release: the long-anticipated MU Origin 2. But for something a little different, the South Korean publisher has launched First Hero. Released today... | Read more »

Price Scanner via MacPrices.net

Amazon drops prices, now offers clearance 13″...
Amazon has new dropped prices on clearance 13″ 2.3GHz Dual-Core non-Touch Bar MacBook Pros by $200 off Apple’s original MSRP, with prices now available starting at $1099. Shipping is free. Be sure to... Read more
2018 15″ MacBook Pros now on sale for $500 of...
Amazon has dropped prices on select clearance 2018 15″ 6-Core MacBook Pros to $500 off Apple’s original MSRP. Prices now start at $1899 shipped: – 2018 15″ 2.2GHz Touch Bar MacBook Pro Silver: $1899.... Read more
Price drop! Clearance 12″ 1.2GHz Silver MacBo...
Amazon has dropped their price on the recently-discontinued 12″ 1.2GHz Silver MacBook to $849.99 shipped. That’s $450 off Apple’s original MSRP for this model, and it’s the cheapest price available... Read more
Apple’s 21″ 3.0GHz 4K iMac drops to only $936...
Abt Electronics has dropped their price on clearance, previous-generation 21″ 3.0GHz 4K iMacs to only $936 shipped. That’s $363 off Apple’s original MSRP, and it’s the cheapest price we’ve seen so... Read more
Amazon’s Prime Day savings on Apple 11″ iPad...
Amazon has new 2018 Apple 11″ iPad Pros in stock today and on sale for up to $250 off Apple’s MSRP as part of their Prime Day sale (but Prime membership is NOT required for these savings). These are... Read more
Prime Day Apple iPhone deal: $100 off all iPh...
Boost Mobile is offering Apple’s new 2018 iPhone Xr, iPhone Xs, and Xs Max for $100 off MSRP. Their discount reduces the cost of an Xs to $899 for the 64GB models and $999 for the 64GB Xs Max. Price... Read more
Clearance 13″ 2.3GHz Dual-Core MacBook Pros a...
Focus Camera has clearance 2017 13″ 2.3GHz/128GB non-Touch Bar Dual-Core MacBook Pros on sale for $169 off Apple’s original MSRP. Shipping is free. Focus charges sales tax for NY & NJ residents... Read more
Amazon Prime Day deal: 9.7″ Apple iPads for $...
Amazon is offering new 9.7″ WiFi iPads with Apple Pencil support for $80-$100 off MSRP as part of their Prime Day sale, starting at only $249. These are the same iPads found in Apple’s retail and... Read more
Amazon Prime Day deal: 10% (up to $20) off Ap...
Amazon is offering discounts on new 2019 Apple AirPods ranging up to $20 (10%) off MSRP as part of their Prime Day sales. Shipping is free: – AirPods with Charging Case: $144.99 $15 off MSRP –... Read more
Amazon Prime Day deal: $50-$80 off Apple Watc...
Amazon has Apple Watch Series 4 and Series 3 models on sale for $50-$80 off Apple’s MSRP as part of their Prime Day deals with prices starting at only $199. Choose Amazon as the seller rather than a... Read more

Jobs Board

*Apple* Systems Architect/Engineer, Vice Pre...
…its vision to be the world's most trusted financial group. **Summary:** Apple Systems Architect/Engineer with strong knowledge of products and services related to Read more
*Apple* Graders/Inspectors (Seasonal/Hourly/...
…requirements. #COVAentryleveljobs ## Minimum Qualifications Some knowledge of agricultural and/or the apple industry is helpful as well as the ability to comprehend, Read more
Best Buy *Apple* Computing Master - Best Bu...
**710003BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Location Number:** 000171-Winchester Road-Store **Job Description:** Read more
Best Buy *Apple* Computing Master - Best Bu...
**709786BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Location Number:** 000430-Orange Park-Store **Job Description:** **What does a Read more
Geek Squad *Apple* Master Consultation Agen...
**709918BR** **Job Title:** Geek Squad Apple Master Consultation Agent **Job Category:** Services/Installation/Repair **Location Number:** 000106-Palmdale-Store Read more
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