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Feb 98 Challenge

Volume Number: 14 (1998)
Issue Number: 2
Column Tag: Programmer's Challenge

Programmer's Challenge

by Bob Boonstra, Westford, MA

Image Decoder

This month's Challenge is much easier to state than it will be to implement. Your task this month is to write a decoder for Graphics Interchange Format images. GIF is a data stream-oriented file format used to define the transmission protocol of LZW-encoded bitmap data. Your code will read a file containing a GIF and draw the image in an offscreen graphics world. There are two versions of the GIF specification; this Challenge includes only the earlier and more common GIF87a format, not the GIF89a format. The format description is too long to include here, but you can find the GIF87a specification at: ftp://ftp.ncsa.uiuc.edu/misc/file.formats/graphics.formats/gif87a.doc

Other useful information on graphics formats in general is available at: http://www.cis.ohio-state.edu/hypertext/faq/usenet/graphics/fileformats-faq/top.html

The prototype for the code you should write is:

#include <QDOffscreen.h>
#include <stdio.h>
GWorldPtr ReadImage(FILE *inputFile);

The inputFile will have been opened for you in binary mode by the calling routine. ReadImage should read and parse the image, create a GWorld with the appropriate color table, draw the image in the GWorld, and return a GWorld pointer to the calling routine. The solution that correctly decodes a variety of images in the least amount of execution time will be the winner.

I thought for some time about the Compuserve / Unisys / LZW patent controverty before selecting this topic for the Challenge. The LZW algorithm used in GIF compression is patented by Unisys, and Unisys requires that any commercial software product that uses this algorithm, including software that reads GIF images, requires a license from Unisys. Freely distributed software does not require a license. Since the Challenge doesn't result in a software product, much less a commercial product, I decided to go ahead with this exploration of decoding efficiency.

This will be a native PowerPC Challenge, using the latest CodeWarrior environment. Solutions must be coded in C, C++, or Pascal. This Challenge was suggested by Peter Lewis, who earns 2 Challenge points for the suggestion.

Three Months Ago Winner

Congratulations to Jeff Mallett (Boulder Creek, CA) for submitting the winning entry to the Pente(tm) Challenge. The objective was to accumulate, in minimum execution time, the most points in a round-robin tournament of the board game Pente(tm). With only three entries, the tournament required only six games for each player to compete against each other player twice, once playing first and once playing second. Both the winning entry and the third-place entry by Randy Boring employed an alpha-beta search technique to find the best move, and both entries were successful in winning most of their games. Jeff's entry, however, was more efficient about pruning the search tree and therefore required significantly less execution time than Randy's entry. Since a point was deducted for each second of execution time, the winning entry lost significantly fewer points for inefficiency. In addition, the scoring algorithm in Jeff's AddStone routine takes advantage of all three methods of scoring points: captures, winning by placing 5 stones in a row, and leaving sequences of 4-in-a-row on the board at the conclusion of a game. His solution earned more points as a result, even though it won the same number of games as Randy's.

The table below lists the number of tournament wins, points earned, cumulative score, code size, data size, and programming language for each entry. The number in parentheses after the entrant's name is the total number of Challenge points earned in all Challenges to date prior to this one.

Name               Wins   Points   Score  Code  Data  Language
Jeff Mallett (74)    3      33     32.03  4872  7923    C
Sebastian Maurer     0      10      9.97  4860  208     C++
Randy Boring (66)    3      23   -374.90  7672  2649    C

Top 20 Contestants

Here are the Top Contestants for the Programmer's Challenge. The numbers below include points awarded over the 24 most recent contests, including points earned by this month's entrants. The scores have been adjusted to correct an error made in assigning points for the Stratego Challenge printed in the November issue.

Rank Name               Points
 1.  Munter, Ernst        200  
 2.  Boring, Randy         73
 3.  Cooper, Greg          61
 4.  Lewis, Peter          59
 5.  Mallett, Jeff         50
 6.  Nicolle, Ludovic      48
 7.  Murphy, ACC           34
 8.  Gregg, Xan            33
 9.  Antoniewicz, Andy     24
10.  Day, Mark             20
11.  Higgins, Charles      20
12.  Larsson, Gustav       20
13.  Studer, Thomas        20
14.  Gundrum, Eric         15
15.  Hart, Alan            14
16.  O'Connor, Turlough    14
17.  Picao, Miguel Cruz    14
18.  Saxton, Tom           12
19.  Cutts, Kevin          11
20.  8-way tie             10

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
2nd place            10 points
3rd place             7 points
4th place             4 points
5th place             2 points
finding bug           2 points
suggesting Challenge  2 points

Here is Jeff's winning solution:

MyPente.c
Copyright © 1997 Jeff Mallett
//
// Do a depth=1 search to sort moves. Then do a higher
// depth alpha-beta search to select the best move.
//
// Plays for score rather than to win. For example,
// doesn't try to win by getting 5 captures since
// there is no score incentive for this. It could be
// retuned to play for a win instead.

#include "Pente.h"

#define SEARCH_DEPTH 4
enum {
 _FRIEND = 0x0001,
 _ENEMY = 0x0002,
 _EMPTY = 0x0004,
 _WALL  = 0x0008
};

#define BORDER    1
#define BORDERS    2
#define INFINITY   32600
#define NA      0
#define MAX_CELLS   (31 + BORDERS) * (31 + BORDERS)

#define ESTIMATE_PLUS 1
#define WIN      2000
#define CAPTURE_SCORE 240
#define VULNERABLE   150

static short CHAIN_SCORE2[3][3] = {  //[color][open]
 { NA, NA, NA },
 { -1, -9, -2 },      // FRIEND
 { 1, 9, 2 }      // ENEMY
};
static short CHAIN_SCORE3[3][3] = {  //[color][open]
 { NA, NA, NA },
 { 3, 16, 40 },      // FRIEND
 { -2,-10,-30 }      // ENEMY
};
static short CHAIN_SCORE4[3][3] = {  //[color][open]
 {  NA, NA, NA },
 { 230, 240, 250 },  // FRIEND
 { -150,-155,-160 }  // ENEMY
};
static short CHAIN_SCORE5[3] = {    //[color]
 NA, WIN, -WIN
};
//                 1  2  3  4
static short BLOCK_SCORE[5] = { NA, 0, 14, 14, 22};
static short THREATS[] = {
 NA, NA,
 25, // 2: tria
 30, // 3: half-open four
 350, // 4: double trias
 370, // 5: tria + half-open four
 450, // 6: tessera or 2 half-open fours
 500, 500, 500, 500, 500, 500, 500, 500, 500, 500
};

static short gPreScore[MAX_CELLS], gEstimates[MAX_CELLS];
static short *gEstimatesStart, *gEstimatesEnd;
static short gBoard[MAX_CELLS], *gBoardStart, *gBoardEnd;
static short *gFirstStone, *gLastStone;
static short *gKillers[SEARCH_DEPTH], gPreviousThreats;
static short gDirections[8], *gDirectionsEnd;
static short gMoveNum, gScore, gStartDepth;
static short gBoardHalfSize, gSideLength, gBoardMax;
static short gCumCapturesFriend, gCumCapturesEnemy;
static short gAdjustment, gSE;

#define ADJUST(a)    ( (a) + gAdjustment )
#define TRANSLATE(x, y) \
 (gSideLength * ADJUST(y) + ADJUST(x))
#define GET_INDEX(p) ((p) - gBoard)
#define GET_X(i)   ( ((i) % gSideLength) - gAdjustment )
#define GET_Y(i)   ( ((i) / gSideLength) - gAdjustment )
#define UPDATE_ENDPOINTS(pSq, a, b) \
 if (pSq < a) a = pSq; \
 if (pSq > b) b = pSq

#define OPPONENT(side) (3 - (side))
#define OCCUPIED(x)   ((x) & (_FRIEND | _ENEMY))
#define EMPTY(x)    ((x) == _EMPTY)

// gChanges -- Array of unsigned longs containing data to
// undo moves
//   list of:
//     <pointer to position> <old position value>
//   terminated by a OL
static unsigned long gChanges[256], *gChangesEnd;
#define PUSH(x)    *(gChangesEnd++) = (x)
#define START_SAVE  PUSH(0L)
#define PUSH_SQ(pSq) \
  { PUSH((long)*(pSq)); PUSH((unsigned long)(pSq)); }
#define POP      *(--gChangesEnd)
#define TOP      *gChangesEnd

static short * ChooseNextMove();
static short AddStone(short alpha, short beta, short *pSq,
        short color, short depth,
        short capturesFriend, short capturesEnemy,
        short *firstStone, short *lastStone);
static long MyFindCaptures(Capture capture[], short *pSq,
        short us, short them);
static Boolean MyFindFive(short *pSq, short color);

InitPente
void InitPente(
 long boardHalfSize  /* e.g., 9 for a 19x19 board */
       /* all coordinates between -boardHalfSize
        and +boardHalfSize */
) {
 short i, j, *pSq;
 
 gBoardHalfSize = boardHalfSize;
 gSideLength = boardHalfSize * 2 + 1 + BORDERS;
 gSE = gSideLength + 1;
 gDirections[0] = -gSE;                // NW
 gDirections[1] = -gSideLength;        // N
 gDirections[2] = -gSideLength + 1;     // NE
 gDirections[3] = -1;                // W
 gDirections[4] = gSE;                // SE
 gDirections[5] = gSideLength;        // S
 gDirections[6] = gSideLength - 1;      // SW
 gDirections[7] = 1;                  // E
 gDirectionsEnd = &gDirections[8];
 
 gBoardMax = gSideLength * gSideLength;
 i = (gSideLength + 1) * BORDER;
 gBoardStart = &gBoard[i];
 gBoardEnd = &gBoard[gBoardMax - i];
 gEstimatesStart = &gEstimates[i];
 gEstimatesEnd = &gEstimates[gBoardMax - i];
 gFirstStone = gBoardEnd;
 gLastStone = gBoardStart;
 
 pSq = gBoard;
 do {
  *pSq = _WALL;
 } while (++pSq != gBoardStart);
 do {
  *pSq = _EMPTY;
 } while (++pSq != gBoardEnd);
 do {
  *pSq = _WALL;
 } while (++pSq < &gBoard[gBoardMax]);
 for (i = BORDER + boardHalfSize * 2 + 1;
    i<gBoardMax-gSideLength; i += gSideLength)
  for (j=0; j<BORDERS; ++j)
   gBoard[i+j] = _WALL;
 gCumCapturesFriend = gCumCapturesEnemy = gMoveNum = 0;
 gAdjustment = gBoardHalfSize + BORDER;
 gStartDepth = SEARCH_DEPTH - 1;
}

Pente
void Pente(
 Point opponentsMove,      /* your opponent moved here */
 Boolean playingFirst,      /* ignore opponentMove */
 Point *yourMove,          /* return your move here */
 Capture claimCaptures[],    /* return captured pairs here */
 long *numCaptures,       /* return # of claimCaptures */
 Boolean *claimVictory     /* return true if you claim
               victory with this move */
) {
 Point move;
 Capture opponentCaptures[8];
 
 short *pSq, *pNewSq, *d;
 short score, bestScore, i;
 short *pBestMove;
 
 *numCaptures = 0;
 *claimVictory = false;
 if (playingFirst) { // *** MOVE 1
  move.h = move.v = 0;
  pSq = &gBoard[TRANSLATE(0, 0)];
  *pSq = _FRIEND;
  UPDATE_ENDPOINTS(pSq, gFirstStone, gLastStone);
  *yourMove = move;
  gMoveNum = 1;
  return;
 }
 
 i = TRANSLATE(opponentsMove.h, opponentsMove.v);
 pSq = &gBoard[i];
 *pSq = _ENEMY;
 UPDATE_ENDPOINTS(pSq, gFirstStone, gLastStone);
 ++gMoveNum;

 if (gMoveNum == 1) { // *** MOVE 2
  move.h = move.v = -2;
  pSq = &gBoard[TRANSLATE(-2, -2)];
  *pSq = _FRIEND;
  UPDATE_ENDPOINTS(pSq, gFirstStone, gLastStone);
  *yourMove = move;
  gMoveNum = 2;
  return;
 }
 
 if (gMoveNum == 2) { // *** MOVE 3
  if (opponentsMove.v < opponentsMove.h) {
   if (opponentsMove.v < -opponentsMove.h) {
    // top triangle
    move.h = 0;
    move.v = 4;
   } else {
    // right triangle
    move.h = -4;
    move.v = 0;
   }
  } else {
   if (opponentsMove.v >= -opponentsMove.h) {
    // bottom triangle
    move.h = 0;
    move.v = -4;
   } else {
    // left triangle
    move.h = 4;
    move.v = 0;
   }
  }
  pSq = &gBoard[TRANSLATE(move.h, move.v)];
  *pSq = _FRIEND;
  UPDATE_ENDPOINTS(pSq, gFirstStone, gLastStone);
  *yourMove = move;
  gMoveNum = 3;
  return;
 }

 gChangesEnd = gChanges;
 gCumCapturesEnemy +=
   MyFindCaptures(opponentCaptures, &gBoard[i],
           _ENEMY, _FRIEND);
 for (pSq = gEstimatesStart; pSq != gEstimatesEnd; ++pSq)
  *pSq = 0;
 for (pSq = gFirstStone; pSq <= gLastStone; ++pSq)
  if (OCCUPIED(*pSq)) {
   d = gDirections;
   do {
    pNewSq = pSq + *d;
    if (EMPTY(*pNewSq)) {
     gEstimates[GET_INDEX(pNewSq)] += ESTIMATE_PLUS;
     pNewSq += *d;
     if (EMPTY(*pNewSq)) {
      gEstimates[GET_INDEX(pNewSq)] += ESTIMATE_PLUS;
     }
    }
   } while (++d != gDirectionsEnd);
  }

 for (pSq = gBoardStart; pSq != gBoardEnd; ++pSq)
  if (gEstimates[GET_INDEX(pSq)]) {
   i = GET_INDEX(pSq);
   gScore = gEstimates[i];
   gPreScore[i] = AddStone(-INFINITY, INFINITY, pSq,
            _FRIEND, 0, gCumCapturesFriend,
            gCumCapturesEnemy, gFirstStone,
            gLastStone);
  }

 for (i=0; i<SEARCH_DEPTH; ++i)
  gKillers[i] = NULL;
 bestScore = -INFINITY;
 pBestMove = NULL;
 pSq = ChooseNextMove();
 while (pSq) {
  i = GET_INDEX(pSq);
  gScore = gEstimates[i];
  score = AddStone(-INFINITY, -bestScore, pSq, _FRIEND,
       gStartDepth, gCumCapturesFriend,
       gCumCapturesEnemy, gFirstStone, gLastStone);
  gEstimates[i] = -1; // searched
  if (score > bestScore) {
   bestScore = score;
   pBestMove = pSq;
  }
  pSq = ChooseNextMove();
 }
  
 if (bestScore == -INFINITY) {
  for (pSq = gBoardStart; pSq != gBoardEnd; ++pSq)
   if (EMPTY(*pSq) && !gEstimates[GET_INDEX(pSq)]) {
    gScore = 0;
    score = AddStone(-INFINITY, -bestScore, pSq, _FRIEND,
                  gStartDepth, gCumCapturesFriend,
                  gCumCapturesEnemy, gFirstStone, gLastStone);
    if (score > bestScore) {
     bestScore = score;
     pBestMove = pSq;
    }
   }
  if (bestScore == -INFINITY) {
   DebugStr("\p no move found - Pente");
   return; //no move
  }
 }
 
 *pBestMove = _FRIEND;
 UPDATE_ENDPOINTS(pBestMove, gFirstStone, gLastStone);
 i = GET_INDEX(pBestMove);
 move.h = GET_X(i);
 move.v = GET_Y(i);
 *yourMove = move;
 ++gMoveNum;
 // find captures
 *numCaptures = MyFindCaptures(claimCaptures, pBestMove,
          _FRIEND, _ENEMY);
 gCumCapturesFriend += *numCaptures;
 if (gCumCapturesFriend >= 5) {
  *claimVictory = true;
 } else {
  *claimVictory = MyFindFive(pBestMove, _FRIEND);
 }
}

TermPente
void TermPente(void) { }

ChooseNextMove
short * ChooseNextMove()
{
 short i, *pSq;
 short *found = NULL;
 short high = -INFINITY;
 for (pSq = gBoardStart; pSq != gBoardEnd; ++pSq) {
  i = GET_INDEX(pSq);
  if (gEstimates[i] > 0 && gPreScore[i] > high) {
   found = pSq;
   high = gPreScore[i];
  }
 }
 return found;
}

AddStone
// Alpha-beta search routine
// returns score of how good it is for color
// alpha and beta apply for the opponent after the move
// is made
// gScore is absolute: + for _FRIEND
short AddStone(short alpha, short beta, short *pSq,
    short color, short depth, short capturesFriend,
    short capturesEnemy, short *firstStone,
    short *lastStone)
{
 register short *pNewSq, *d;
 short x, bestScore, t, *pEnd;
 short open, *killer;
 short threats, blocks, vulnerable;
 short opponent = OPPONENT(color);
 short saveScore = gScore;
  
 START_SAVE;
 threats = blocks = vulnerable = 0;
 d = gDirections;
 do {
  pNewSq = pSq + *d;
  
  if (*pNewSq == color) { // Next to friend
   if (d <= &gDirections[3]) {
    x = 1;
    open = 0;
    for (pNewSq += *d; *pNewSq == color; pNewSq += *d)
     ++x;
    if (EMPTY(*pNewSq))
     open = 1;
    for (pNewSq = pSq + *(d+4); *pNewSq == color;
       pNewSq += *(d+4))
     ++x;
    if (EMPTY(*pNewSq))
     ++open;
   } else {
    t = *(pSq + *(d-4));
    if (t == color)
     continue;
    x = 1;
    open = 0;
    if (EMPTY(t))
     open = 1;
    for (pNewSq += *d; *pNewSq == color; pNewSq += *d)
     ++x;
    if (EMPTY(*pNewSq))
     ++open;
   }
   
   switch (x) {
    case 1:  // 2-in-a-row
     gScore += CHAIN_SCORE2[color][open];
     if (open == 1)
      ++vulnerable;
     break;
    case 2:  // 3-in-a-row
     gScore += CHAIN_SCORE3[color][open];
     if (open == 2)
      threats += 2;        // tria = 2
     break;
    case 3:  // 4-in-a-row
     gScore += CHAIN_SCORE4[color][open];
     threats += open * 3;  // tessera = 6, half-open = 3
     break;
    default:  // 5-in-a-row (or more)
     gScore += CHAIN_SCORE5[color];
     threats = -99;        // game over
     break;
   }
   
  } else if (*pNewSq == opponent) {  // Next to enemy
   x = 1;
   for (pNewSq += *d; *pNewSq == opponent; pNewSq += *d)
    ++x;
    
   if (EMPTY(*pNewSq)) {
    blocks += BLOCK_SCORE[x];
   } else if (x == 2 && *pNewSq == color) {
    t = CAPTURE_SCORE;
    if (color != _FRIEND)
     t = -t;
    gScore += t;
    if (color == _FRIEND) {
     if (++capturesFriend >= 5) {
      threats = -99;  // game over
     }
    } else {  // color == _ENEMY
     if (++capturesEnemy >= 5) {
      threats = -99;  // game over
     }
    }
    if (depth) {
     pNewSq = pSq + *d;
     PUSH_SQ(pNewSq);
     *pNewSq = _EMPTY;
     pNewSq += *d;
     PUSH_SQ(pNewSq);
     *pNewSq = _EMPTY;
    }
   }
  }
 } while (++d != gDirectionsEnd);
  
 if (threats < 0) {
  // Game over
  bestScore = gScore;
  if (color != _FRIEND)
   bestScore = -bestScore;
  goto RESTORE;
 }
   
  // Not forced to make a bad move
 if (color == _FRIEND) {
  if (gScore < saveScore)
   gScore = saveScore;
 } else if (gScore > saveScore)
  gScore = saveScore;
 if (depth) {
  // Add stone
  PUSH_SQ(pSq);
  *pSq = color;
  UPDATE_ENDPOINTS(pSq, firstStone, lastStone);
  --depth; 
  gPreviousThreats = threats;
  bestScore = -INFINITY;
  // Killer move?
  killer = gKillers[depth];
  if (killer && EMPTY(*killer)) {
   saveScore = gScore;
    bestScore = AddStone(-beta, -alpha, killer,
           opponent, depth, capturesFriend,
           capturesEnemy, firstStone, lastStone);
   gScore = saveScore;
   if (bestScore > alpha) {
    if (bestScore >= beta) {
     bestScore = -bestScore;
     goto RESTORE;
    }
    alpha = bestScore;
   }
  }
  
  pEnd = lastStone + gSE;
  if (pEnd >= gBoardEnd)
   pEnd = gBoardEnd - 1;
  pSq = firstStone - gSE;
  if (pSq < gBoardStart)
   pSq = gBoardStart;
  do {
   if (EMPTY(*pSq) && pSq != killer) {
    d = gDirections;
    do {
     pNewSq = pSq + *d;
     if (OCCUPIED(*pNewSq) &&
        (*(pNewSq + *d) == *pNewSq ||
         *(pSq  - *d) == *pNewSq))
      break;
    } while (++d != gDirectionsEnd);
    if (d != gDirectionsEnd) {
     saveScore = gScore;
      t = AddStone(-beta, -alpha, pSq, opponent,
         depth, capturesFriend, capturesEnemy,
         firstStone, lastStone);
     gScore = saveScore;
     if (t > bestScore) {
      bestScore = t;
      if (t > alpha) {
       if (t >= beta) {
        gKillers[depth] = pSq;
        break;
       }
       if (depth >= gStartDepth-1)
        gKillers[depth] = pSq;
       alpha = t;
      }
     }
    }
   }
  } while (++pSq <= pEnd);
  if (bestScore == -INFINITY) {
   ++depth;
   goto TERMINAL;
  }
  bestScore = -bestScore;
  
 } else { // !depth
TERMINAL:
  bestScore = gScore;
  if (color != _FRIEND)
   bestScore = -bestScore;

  // Winning threats
  if (gPreviousThreats >= 5) {
   bestScore -= THREATS[gPreviousThreats];
  } else if (threats >= 5) {
   bestScore += THREATS[threats];
  } else if (gPreviousThreats == 4) {
   bestScore -= THREATS[gPreviousThreats];
  } else if (threats == 4) {
   bestScore += THREATS[threats];
  } else if (gPreviousThreats) {
   bestScore -= THREATS[gPreviousThreats];
  } else if (threats) {
   bestScore += THREATS[threats];
  }
  bestScore += blocks - vulnerable * VULNERABLE;
 }
 
RESTORE: 
 while (POP) {
  pSq = (short *)TOP;
  *pSq = POP;
 }
  
 return bestScore;
}

MyFindCaptures
long MyFindCaptures(Capture capture[], short *pSq,
          short us, short them)
{
 short i, *p1, *p2;
 short myCaptures = 0;
 short *d = gDirections;
 
 do {
  p1 = pSq + *d;
  if (*p1 == them) {
   p2 = p1 + *d;
   if (*p2 == them && *(p2 + *d) == us) {
    *p1 = *p2 = _EMPTY;
    i = GET_INDEX(p1);
    capture[myCaptures].stone1.h = GET_X(i);
    capture[myCaptures].stone1.v = GET_Y(i);
    i = GET_INDEX(p2);
    capture[myCaptures].stone2.h = GET_X(i);
    capture[myCaptures].stone2.v = GET_Y(i);
    ++myCaptures;
   }
  }
 } while (++d != gDirectionsEnd);
 return myCaptures;
}

MyFindFive
Boolean MyFindFive(short *pSq, short color)
{
 short x, *d, *pNewSq, i;
 
 d = gDirections;
 i = 0;
 do {
  x = 1;
  for (pNewSq = pSq + *d; *pNewSq == color; pNewSq += *d)
   ++x;
  for (pNewSq = pSq + *(d+4); *pNewSq == color;
     pNewSq += *(d+4))
   ++x;
  if (x >= 5)
   return true;
  ++d;
 } while (++i < 4);
 return false;
}
 

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Dash is an API documentation browser and code snippet manager. Dash helps you store snippets of code, as well as instantly search and browse documentation for almost any API you might use (for a full... Read more
FotoMagico 5.6.8 - Powerful slideshow cr...
FotoMagico lets you create professional slideshows from your photos and music with just a few, simple mouse clicks. It sports a very clean and intuitive yet powerful user interface. High image... Read more
Civilization VI 1.2.4 - Next iteration o...
Sid Meier’s Civilization VI is the next entry in the popular Civilization franchise. Originally created by legendary game designer Sid Meier, Civilization is a strategy game in which you attempt to... Read more
Skype 8.52.0.138 - Voice-over-internet p...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
Bookends 13.2.6 - Reference management a...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Bookends uses the cloud to sync reference libraries on all the Macs you use.... Read more
BusyContacts 1.4.0 - Fast, efficient con...
BusyContacts is a contact manager for OS X that makes creating, finding, and managing contacts faster and more efficient. It brings to contact management the same power, flexibility, and sharing... Read more
Chromium 77.0.3865.75 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 77.0.3865.75: A list of changes is available... Read more

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Yoozoo Games launches Saint Seiya Awaken...
If you’re into your anime, you’ve probably seen or heard of Saint Seiya. Based on a shonen manga by Masami Kurumada, the series was massively popular in the 1980s – especially in its native Japan. Since then, it’s grown into a franchise of all... | Read more »
Five Nights at Freddy's AR: Special...
Five Nights at Freddy's AR: Special Delivery is a terrifying new nightmare from developer Illumix. Last week, FNAF fans were sent into a frenzy by a short teaser for what we now know to be Special Delivery. Those in the comments were quick to... | Read more »
Rush Rally 3's new live events are...
Last week, Rush Rally 3 got updated with live events, and it’s one of the best things to happen to racing games on mobile. Prior to this update, the game already had multiplayer, but live events are more convenient in the sense that it’s somewhat... | Read more »
Why your free-to-play racer sucks
It’s been this way for a while now, but playing Hot Wheels Infinite Loop really highlights a big issue with free-to-play mobile racing games: They suck. It doesn’t matter if you’re trying going for realism, cart racing, or arcade nonsense, they’re... | Read more »
Steam Link Spotlight - The Banner Saga 3
Steam Link Spotlight is a new feature where we take a look at PC games that play exceptionally well using the Steam Link app. Our last entry talked about Terry Cavanaugh’s incredible Dicey Dungeons. Read about how it’s a great mobile experience... | Read more »
PSA: GRIS has some issues
You may or may not have seen that Devolver Digital just released GRIS on the App Store, but we wanted to do a quick public service announcement to say that you might not want to hop on buying it just yet. The puzzle platformer has come to small... | Read more »
Combo Quest (Games)
Combo Quest 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: Combo Quest is an epic, time tap role-playing adventure. In this unique masterpiece, you are a knight on a heroic quest to retrieve... | Read more »
Hero Emblems (Games)
Hero Emblems 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: ** 25% OFF for a limited time to celebrate the release ** ** Note for iPhone 6 user: If it doesn't run fullscreen on your device... | Read more »
Puzzle Blitz (Games)
Puzzle Blitz 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Puzzle Blitz is a frantic puzzle solving race against the clock! Solve as many puzzles as you can, before time runs out! You have... | Read more »
Sky Patrol (Games)
Sky Patrol 1.0.1 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.1 (iTunes) Description: 'Strategic Twist On The Classic Shooter Genre' - Indie Game Mag... | Read more »

Price Scanner via MacPrices.net

Preorder your Apple Watch Series 5 today at A...
Amazon has Apple Watch Series 5 GPS models available for preorder and on sale today for $15 off Apple’s MSRP. Shipping is free and starts on September 20th: – 40mm Apple Watch Series 5 GPS: $384.99 $... Read more
21″ iMacs on sale for $100 off Apple’s MSRP,...
B&H Photo has new 21″ Apple iMacs on sale for $100 off MSRP with models available starting at $999. These are the same iMacs offered by Apple in their retail and online stores. Overnight shipping... Read more
2018 4 and 6-Core Mac minis on sale today for...
Apple resellers are offering new 2018 4-Core and 6-Core Mac minis for $100-$150 off MSRP for a limited time. B&H Photo has the new 2018 4-Core and 6-Core Mac minis on sale for up to $150 off... Read more
Save $150-$250 on 10.2″ WiFi + Cellular iPads...
Verizon is offering $150-$250 discounts on Apple’s new 10.2″ WiFi + Cellular iPad with service. Buy the iPad itself and save $150. Save $250 on the purchase of an iPad along with an iPhone. The fine... Read more
Apple continues to offer 13″ 2.3GHz Dual-Core...
Apple has Certified Refurbished 2017 13″ 2.3GHz Dual-Core non-Touch Bar MacBook Pros available starting at $1019. An standard Apple one-year warranty is included with each model, outer cases are new... Read more
Apple restocks 2018 MacBook Airs, Certified R...
Apple has restocked Certified Refurbished 2018 13″ MacBook Airs starting at only $849. Each MacBook features a new outer case, comes with a standard Apple one-year warranty, and is shipped free. The... Read more
Sunday Sale! 2019 27″ 5K 6-Core iMacs for $20...
B&H Photo has the new 2019 27″ 5K 6-Core iMacs on stock today and on sale for up to $250 off Apple’s MSRP. Overnight shipping is free to many locations in the US. These are the same iMacs sold by... Read more
Weekend Sale! 2019 13″ MacBook Airs for $200...
Amazon has new 2019 13″ MacBook Airs on sale for $200 off Apple’s MSRP, with prices starting at $899, each including free shipping. Be sure to select Amazon as the seller during checkout, rather than... Read more
2019 15″ MacBook Pros now on sale for $350-$4...
B&H Photo has Apple’s 2019 15″ 6-Core and 8-Core MacBook Pros on sale today for $350-$400 off MSRP, starting at $2049, with free overnight shipping available to many addresses in the US: – 2019... Read more
Buy one Apple Watch Series 5 at Verizon, get...
Buy one Apple Watch Series 5 at Verizon, and get a second Watch for 50% off. Plus save $10 on your first month of service. The fine print: “Buy Apple Watch, get another up to 50% off on us. Plus $10... Read more

Jobs Board

*Apple* Mobility Pro-Store 149 - Best Buy (U...
**731985BR** **Job Title:** Apple Mobility Pro-Store 149 **Job Category:** Store Associates **Location Number:** 000149-Towson-Store **Job Description:** At Best Read more
Student Employment (Blue *Apple* Cafe) Spri...
Student Employment (Blue Apple Cafe) Spring 2019 Penn State University Campus/Location: Penn State Brandywine Campus City: Media, PA Date Announced: 12/20/2018 Date Read more
Windows/ *Apple* Technical Support Engineer...
Windows/ Apple Technical Support Engineer McLean , VA , US Apply + Be you + Be Booz Allen + Be empowered + Learn More Job Description Location: McLean, VA, US Job Read more
*Apple* Mobile Master - Best Buy (United Sta...
**725617BR** **Job Title:** Apple Mobile Master **Job Category:** Store Associates **Location Number:** 001095-Chesterfield-Store **Job Description:** **What does a Read more
Geek Squad *Apple* Master Consultation Agen...
**732415BR** **Job Title:** Geek Squad Apple Master Consultation Agent **Job Category:** Services/Installation/Repair **Location Number:** 000425-Hickory-Store **Job Read more
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