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Jul 98 Prog Challenge

Volume Number: 14 (1998)
Issue Number: 7
Column Tag: Programmer's Challenge

Jul 97 Programmer's Challenge

by Bob Boonstra, Westford, MA

Going Up?

Welcome to the Programmer's Challenge Skyscraper. Your Challenge this month is to assume control of our skyscraper's elevators and efficiently move a dedicated crew of simulated employees up and down the building.

The prototype for the code you should write is:

#if defined(__cplusplus)
extern "C" {
#endif

#define kMaxFloors 500
#define kMaxElevators 100
#define kElevatorCapacity 16

typedef enum {         /* commanded action for elevator car */
  kGoingUp=1,          /* send car up one floor */
  kGoingDown,          /* send car down one floor */
  kStoppedGoingUp,     /* stop car at an intermediate floor, car going up */
  kStoppedGoingDown,   /* stop car at an intermediate floor, car going down */
  kStoppedIdle         /* stop car, car in idle state */
} CarAction;

typedef struct CarState {
  long atFloor;        /* current location of car */
  long goingToFloor[kMaxFloors];
    /* goingToFloor[i] is the number of passengers in the car is going to floor [i] */
 } CarState;

typedef Boolean (*AdvanceTimeProc) (
                      /* return value of TRUE means Elevator should exit */
  CarAction action[kMaxElevators],  /* direction you move each elevator */
  CarState newState[kMaxElevators],  /* returns new state of each elevator */
  Boolean stopsAtFloor[kMaxFloors],
     /* stopsAtFloor[i]==TRUE means elevator stops at floor i */
  Boolean callGoingUp[kMaxFloors], 
     /* callGoingUp[i]==TRUE means a passenger on floor i wants to go up */
  Boolean callGoingDown[kMaxFloors]
     /* callGoingDown[i]==TRUE means a passenger on floor i wants to go down */
);

void Elevator(
  long numFloors,     /* number of floors in our building, < kMaxFloors */
  long numElevators,  /* number of elevators in our building, <
                         kMaxElevators */
  AdvanceTimeProc AdvanceTime  /* callback to get new state */
);
#if defined(__cplusplus)
}
#endif

Your Elevator routine will be called with the number of floors (numFloors) in our simulated skyscraper, the number of elevators (numElevators) at your command, and a callback routine (AdvanceTime). You should repeatedly call AdvanceTime, commanding an action and a set of constraints (stopsAtFloor) for each elevator car and receiving back the newState of each car. AdvanceTime will also provide an indicator of whether any prospective passengers on floor i have called an elevator to take them higher (callGoingUp[i]) or lower (callGoingDown[i]).

The newState returned by AdvanceTime provides the location of each car and the number of occupants. atFloor is the floor at which the car is now located. Our elevator passengers are extraordinarily cooperative -- on entering, they all indicate their destination by pressing the button corresponding to their floor, whether or not that floor has already been selected, allowing AdvanceTime to give you an accurate count of the passengers going to floor i (goingToFloor[i]). Our passengers are also extraordinarily swift --they exit and enter in such an orderly fashion that the passenger exchange takes place in one time step.

Each call to AdvanceTime will move all the elevators one floor in the direction you indicate. If you stop the car by setting action to kStoppedGoingUp, kStoppedGoingDown, or kStoppedIdle, passengers headed for the current floor will exit and new passengers, up to kElevatorCapacity, will enter. Almost always, passengers headed to higher (or lower) floors will only enter elevators that are kStoppedGoingUp (kStoppedGoingDown) or kStoppedIdle, but occasionally someone will be confused and enter an elevator headed in the wrong direction.

You are free to run your elevators anyway you see fit, except that a car declared to be kGoingUp (or kGoingDown) needs to continue going up (or down) until all passengers headed in that direction have exited. You can designate elevators to be express elevators by setting stopsAtFloor[i] to be FALSE for floors where this elevator does not stop. Passengers will only enter cars that will stop at their intended destination. You can change the stopsAtFloor values at any time, but you need to be careful not to strand passengers -- you can command the car to stop at any time, but the door will only open at floor i if stopsAtFloor[i] is TRUE.

The objective of this Challenge is to deliver passengers to their destinations as expeditiously as possible. You incur a cost of one point for each passenger for each time step from the time s/he presses the call button until the time s/he exits the elevator. You also incur one point for each 10 milliseconds of execution time, including the time spent by AdvanceTime. Stranding a passenger inside an elevator or not responding to an elevator call button results in disqualification of your solution. The solution that incurs the fewest points wins the Challenge. There are no storage constraints for this Challenge, except that it must execute on my 96MB 8500/200.

The Challenge will simulate a normal workday in our simulated skyscraper. People arrive at the beginning of the day either by entering the parking garage at floor 0 or by walking into the main entrance at floor 1. They work in approximately equal numbers on floors 2 through numFloors-1. During the day, they move about the building as necessary. Somewhere in the middle of the day, most of them take a lunch break, either at the cafeteria on floor 2 or by leaving the building. Nearly everyone leaves the building at the end of the day. However, as advanced as our elevators are, they don't have a clock, so you'll have to establish your strategy without knowing the time of day.

This will be a native PowerPC Challenge, using the latest CodeWarrior environment. Solutions may be coded in C, C++, or Pascal. Ernst Munter wins two Challenge points for suggesting this problem, way back in November, 1996.

Three Months Ago Winner

Congratulations to Sebastian Maurer for submitting the winning entry to the April Mancala Challenge. Sebastian won a round-robin tournament whose object was to efficiently capture the most stones in a variant of the ancient game of Mancala. In our variant of the game, the number of bowls ranged from 8 to 32, instead of the traditional 14, and players were allowed to move in either the clockwise or counter-clockwise directions. Congratulations also to JG Heithcock, whose solution actually captured more stones than Sebastian's did, but used better than 50% more execution time to do so. Both of the top solutions used an alpha-beta minmax technique to identify the best move, but Sebastian's heuristic for pruning the tree, combined with the time penalty of one stone per 100ms of execution time, gave him the higher overall score. Sebastian gained a little extra efficiency by partitioning his code into two parallel versions, one for playing first and another for playing second.

Twelve people submitted Mancala solutions, and eleven of those solutions participated in the tournament. (One solution occasionally made illegal moves, so it was eliminated to avoid unevenly affecting the scores of the other players.) The tournament consisted of seven test cases, with board sizes of 8, 12, 16, 20, 24, 28, and 32 bowls. Each solution played against each other solution twice in each test case, once playing first, and once playing second. The top solutions all used some variant of the minmax algorithm, while the lower ranking solutions used simpler heuristics, like always favoring moves that dropped the last stone into their mancala.

The table below lists the results of the tournament, with the solutions ranked in order of total points earned. It lists total execution time for the tournament, the total number of stones captured, the solution rank if execution time had been ignored, total points earned, as well as code size, data size, and programming language used. As usual, 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.

NameTime (secs)Cum StonesRank (stones)Cum PointsCode SizeData SizeLang
Sebastian Maurer (10)54.1614764214222.403488136C
JG Heithcock85.3714897114043.26178448C++
Ken Krugler97.4514627313652.464288308C++
Randy Boring (73)59.9014055413456.028048824C
Eric Kenninga21.1013399513187.9914584894C++
Willeke Rieken (47)3.6311667611630.7440888C++
Simon Jensen-Fellows0.3311512711508.6833646147C, Res
Dennis Jones (10)2.7610383910355.412556125C++
Eric Hangstefer (9)0.05102521010251.543724124C
Ernst Munter (362)104.7611178810130.42791613C++
Josh Cooley0.279446119443.29222864C
K. H.0.00Errors120.003772104C++

Top Contestants

Here are the Top Contestants for the Programmer's Challenge, including everyone who has accumulated more than 10 points during the past two years. The numbers below include points awarded over the 24 most recent contests, including points earned by this month's entrants.

  1. Munter, Ernst 210 points
  2. Boring, Randy 70 points
  3. Cooper, Greg 61 points
  4. Mallett, Jeff 50 points
  5. Rieken, Willeke 47 points
  6. Nicolle, Ludovic 34 points
  7. Lewis, Peter 31 points
  8. Maurer, Sebastian 30 points
  9. Gregg, Xan 24 points
  10. Murphy, ACC 24 points
  11. Hart, Alan 21 points
  12. Antoniewicz, Andy 20 points
  13. Day, Mark 20 points
  14. Higgins, Charles 20 points
  15. Hostetter, Mat 20 points
  16. Studer, Thomas 20 points

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 Sebastian's winning solution to the Mancala Challenge:

Mancala.C
Copyright 1998, Sebastian M. Maurer

#include <stdio.h>
#include "Mancala.h"

enum { kDefault, kPlayAgain, kGameOver };
typedef long StateOfGame;

// There are two versions of almost every routine
// so we don't have to decide at run time
// which side to play on. It speeds things up a
// little bit
// AlphaBeta1 and AlphaBeta2 are the recursive searchers
// for each of the two players. They return the value of
// best move (returned in *chosenBowl, *chosenDirection).
// For a description of Minimax and Alphabeta searches,
// see Peter Norvig's
// "Paradigms of Artificial Intelligence Programming"

#define kMaxSignedLong    0x7FFFFFFF

Prototypes
long AlphaBeta1(
  long depth,
  long board[],
  long *boardStorage,
  const long boardSize,
  long *chosenBowl,
  long *chosenDirection,
  long lowerBound,
  /* any big negative number to enter recursion */
  long upperBound      
  /* any big positive number to enter recursion */
);

long AlphaBeta2(
  long depth,
  long board[],
  long *boardStorage,
  const long boardSize,
  long *chosenBowl,
  long *chosenDirection,
  long lowerBound,
  long upperBound
);

// DropStones -- play the move
// Return true if we get to play again

Boolean DropStones1(
  long board[],
  const long boardSize,
  long bowlPlayed,
  long directionPlayed
);

Boolean DropStones2(
  long board[],
  const long boardSize,
  long bowlPlayed,
  long directionPlayed
);

// SideEmpty returns true if the side is empty
// (and the game is over)

Boolean FirstSideEmpty(
  long board[],
  const long halfBoardSize
);

Boolean SecondSideEmpty(
  long board[],
  const long boardSize
);
// Moves all the remaining stones
// to the appropriate Mancala

void RemainingToMancala(
  long board[],
  const long boardSize,
  const Boolean playerOne
);

// DoMove Drops the stones, checks if the game
// is over (if so, cleans up the board), and
// returns kGameOver, kPlayAgain, or kDefault
StateOfGame DoMove1(
  long board[],
  const long boardSize,
  long bowlPlayed,
  long directionPlayed
);

StateOfGame DoMove2(
  long board[],
  const long boardSize,
  long bowlPlayed,
  long directionPlayed
);

// Called only once from
// within Mancala
Boolean ClaimingVictory(
  long board[],
  const long boardSize,
  const Boolean playerOne
);

Mancala
Boolean Mancala(        /* return true if claiming victory */
  long board[]          /* on entry, board[i] is number of stones in bowl i */
                      /* on exit, board reflects the results of your move */
  const long boardSize,  /* number of bowls in the board, including mancalas */
  void *privStorage,    /* pointer to 1MB of storage for your use */
  const Boolean newGame,  /* true for your first move of a game */
  const Boolean playerOne,  /* true when you are the first player */
  long *bowlPlayed,        /* return the number of the bowl you played from */
  long *directionPlayed    /* return 1 if you played counter-clockwise, */
                        /* return -1 if you played clockwise */
)
{
#pragma unused(newGame)
  // Q&D way to decide how far to search
  // so that we don't lose too much time
  long depth;
  switch (boardSize)
  {
    case 8: depth = 10; break;
    case 10: depth = 8; break;
    case 12:
    case 14: depth = 6; break;
    case 16: 
    case 18: depth = 5; break;
    case 20: 
    case 22: 
    case 24: 
    case 26: depth = 4; break;
    case 28: 
    case 30: 
    case 32: depth = 3; break;
    default: depth = 1; break;
  }

  // Start recursion and play move
  if (playerOne) {
    AlphaBeta1(depth, board, (long*)privStorage,
      boardSize, bowlPlayed, directionPlayed,
      -kMaxSignedLong, kMaxSignedLong);
    DropStones1(board, boardSize,
      *bowlPlayed, *directionPlayed);
  }
  else
  {
    AlphaBeta2(depth, board, (long*)privStorage,
      boardSize, bowlPlayed, directionPlayed,
      -kMaxSignedLong, kMaxSignedLong);
    DropStones2(board, boardSize,
      *bowlPlayed, *directionPlayed);
  }
  
  // Correct to proper convention
  *directionPlayed = - (*directionPlayed);
  return ClaimingVictory(board, boardSize, playerOne);
}

AlphaBeta1
long AlphaBeta1(
  long depth,
  long board[],
  long *boardStorage,
  const long boardSize,
  long *chosenBowl,
  long *chosenDirection,
  long lowerBound,
  long upperBound
)
{
  long myMancala, hisMancala, firstBowl, halfBoardSize;
  long bowl, dir, value, bestBowl, bestDir;
  long *workingBoard;
  
  halfBoardSize = boardSize / 2;
  workingBoard = boardStorage + depth * boardSize;
  myMancala = 0;
  hisMancala = halfBoardSize;
  firstBowl = 1;
  
  for (bowl = firstBowl; bowl < hisMancala; bowl++)
    if (board[bowl] > 0)
    {
      StateOfGame result;
      long i;

      dir = -1;

      // The following trick speeds the whole program
      // up by about 1 percent... take it or leave it
      for (i = 0; i < halfBoardSize; i++)
        ((double*)workingBoard)[i] =
          ((double*)board)[i];
        
      result = DoMove1(workingBoard, boardSize,
                bowl, dir);
      if ((depth == 0) || (result == kGameOver))
        value = workingBoard[myMancala] -
              workingBoard[hisMancala];
      else
      {
        if (result == kPlayAgain)
          value = AlphaBeta1(
                depth - 1, workingBoard,
                boardStorage, boardSize,
                chosenBowl, chosenDirection,
                lowerBound, upperBound);
        else
          value = - AlphaBeta2(
                depth - 1, workingBoard,
                boardStorage, boardSize,
                chosenBowl, chosenDirection,
                - upperBound, - lowerBound);
      }

      if (value > lowerBound)
      {
        bestBowl = bowl;
        bestDir = dir;
        lowerBound = value;
        
        if (lowerBound >= upperBound)
          break;
      }

      dir = 1;

      for (i = 0; i < halfBoardSize; i++)
        ((double*)workingBoard)[i] =
          ((double*)board)[i];
        
      result = DoMove1(workingBoard, boardSize, bowl, dir);
      if ((depth == 0) || (result == kGameOver))
        value = workingBoard[myMancala] -                   workingBoard[hisMancala];
      else
      {
        if (result == kPlayAgain)
          value = AlphaBeta1(
                depth - 1, workingBoard,
                boardStorage, boardSize,
                chosenBowl, chosenDirection,
                lowerBound, upperBound);
        else
          value = - AlphaBeta2(
                depth - 1, workingBoard,
                boardStorage, boardSize,
                chosenBowl, chosenDirection,
                - upperBound, - lowerBound);
      }

      if (value > lowerBound)
      {
        bestBowl = bowl;
        bestDir = dir;
        lowerBound = value;
        
        if (lowerBound >= upperBound)
          break;
      }
      
    }
  
  *chosenBowl = bestBowl;
  *chosenDirection = bestDir;
  return lowerBound;
}

AlphaBeta2
long AlphaBeta2(
  long depth,
  long board[],
  long *boardStorage,
  const long boardSize,
  long *chosenBowl,
  long *chosenDirection,
  long lowerBound,
  long upperBound
)
{
  long myMancala, hisMancala, firstBowl, halfBoardSize;
  long bowl, dir, value, bestBowl, bestDir;
  long *workingBoard;
  
  halfBoardSize = boardSize / 2;

  workingBoard = boardStorage + depth * boardSize;
  myMancala = halfBoardSize;
  hisMancala = 0;
  firstBowl = myMancala + 1;
  for (bowl = firstBowl; bowl < boardSize; bowl++)
    if (board[bowl] > 0)
    {
      long i, result;

      dir = -1;

      for (i = 0; i < halfBoardSize; i++)
        ((double*)workingBoard)[i] =
          ((double*)board)[i];
      
      result = DoMove2(workingBoard, boardSize,
                bowl, dir);
    if ((depth == 0) || (result == kGameOver))
        value = workingBoard[myMancala] -
              workingBoard[hisMancala];
      else
      {
        if (result == kPlayAgain)
          value = AlphaBeta2(
                depth - 1, workingBoard,
                boardStorage, boardSize,
                chosenBowl, chosenDirection,
                lowerBound, upperBound);
        else
          value = - AlphaBeta1(
                depth - 1, workingBoard,
                boardStorage, boardSize,
                chosenBowl, chosenDirection,
                - upperBound, - lowerBound);
      }
      if (value > lowerBound)
      {
        bestBowl = bowl;
        bestDir = dir;
        lowerBound = value;
        if (lowerBound >= upperBound)
          break;
      }
      
      dir = 1;
      
      for (i = 0; i < halfBoardSize; i++)
        ((double*)workingBoard)[i] =
          ((double*)board)[i];

      result = DoMove2(workingBoard, boardSize,
                bowl, dir);
      if ((depth == 0) || (result == kGameOver))
        value = workingBoard[myMancala] -
              workingBoard[hisMancala];
      else
      {
        if (result == kPlayAgain)
          value = AlphaBeta2(
                depth - 1, workingBoard,
                boardStorage, boardSize,
                chosenBowl, chosenDirection,
                lowerBound, upperBound);
        else
          value = - AlphaBeta1(
                depth - 1, workingBoard,
                boardStorage, boardSize,
                chosenBowl, chosenDirection,
                - upperBound, - lowerBound);
      }

      if (value > lowerBound)
      {
        bestBowl = bowl;
        bestDir = dir;
        lowerBound = value;
        if (lowerBound >= upperBound)
          break;
      }

    }
  
  *chosenBowl = bestBowl;
  *chosenDirection = bestDir;
  return lowerBound;
}

DropStones1
/***
Boolean DropStones()
Drops stones, return true if we get to play again
***/

inline Boolean DropStones1(
  long board[],
  const long boardSize,
  long bowlPlayed,
  long directionPlayed
)
{
  long myMancala, hisMancala, firstBowl, lastBowl;
  long stonesInHand, nextBowl;

  myMancala = 0;
  hisMancala = boardSize / 2;
  firstBowl = 1;
  lastBowl = hisMancala - 1;

  stonesInHand = board[bowlPlayed];
  board[bowlPlayed] = 0;
  nextBowl = bowlPlayed;
  /* Drop stones */
  while (stonesInHand > 0) {
    nextBowl += directionPlayed;
    
    if (nextBowl == hisMancala)
      nextBowl += directionPlayed;
    else
    {
      if (nextBowl < 0)
        nextBowl = boardSize - 1;
      else
        if (nextBowl == boardSize)
          nextBowl = 0;
    }
    board[nextBowl] += 1;
    stonesInHand -= 1;
  }
  
  /* Perform capture */
  if ((board[nextBowl] == 1) &&
    (nextBowl >= firstBowl) &&
    (nextBowl <= lastBowl))
  {
    board[nextBowl] = 0;
    board[myMancala] += 
      (1 + board[boardSize - nextBowl]);
    board[boardSize - nextBowl] = 0;
  }
  
  /* Return true if get to play again */
  return (nextBowl == myMancala);
}

DropStones2
inline Boolean DropStones2(
  long board[],
  const long boardSize,
  long bowlPlayed,
  long directionPlayed
)
{
  long myMancala, firstBowl, lastBowl;
  long stonesInHand, nextBowl;

  myMancala = boardSize / 2;
  firstBowl = myMancala + 1;
  lastBowl = boardSize - 1;

  stonesInHand = board[bowlPlayed];
  board[bowlPlayed] = 0;
  nextBowl = bowlPlayed;
  /* Drop stones */
  while (stonesInHand > 0) {
    nextBowl += directionPlayed;
    
    if (nextBowl <= 0)
      nextBowl = boardSize - 1;
    else
      if (nextBowl == boardSize)
        nextBowl = 1;
    board[nextBowl] += 1;
    stonesInHand -= 1;
  }
  
  /* Perform capture */
  if ((board[nextBowl] == 1) &&
    (nextBowl >= firstBowl) &&
    (nextBowl <= lastBowl))
  {
    board[nextBowl] = 0;
    board[myMancala] +=
      (1 + board[boardSize - nextBowl]);
    board[boardSize - nextBowl] = 0;
  }
  
  /* Return true if get to play again */
  return (nextBowl == myMancala);
}

FirstSideEmpty
/*
Boolean FirstSideEmpty()
Checks to see if first side has no stones left in it
*/
inline Boolean FirstSideEmpty(
  long board[],
  const long halfBoardSize
) 
{
  long bowl;
  for(bowl = halfBoardSize - 1; bowl > 0; bowl--)
    if (board[bowl] != 0)
      return false;
  return true;
}


SecondSideEmpty
/*
Boolean SecondSideEmpty()
Checks to see if first side has no stones left in it
*/
inline Boolean SecondSideEmpty(
  long board[],
  const long boardSize
) 
{
  long bowl;
  long halfBoardSize = boardSize / 2;
  for(bowl = boardSize - 1; bowl > halfBoardSize; bowl--)
    if (board[bowl] != 0)
      return false;
  return true;
}

RemainingToMancala
/*
void RemainingToMancala()
Moves remaining stones on specified side into Mancala
*/
inline void RemainingToMancala(
  long board[],
  const long boardSize,
  const Boolean playerOne
)
{
  long mancala, firstBowl, lastBowl, bowl;

  if (playerOne) {
    mancala = 0;
    firstBowl = 1;
    lastBowl = boardSize / 2 - 1;
  } else {
    mancala = boardSize / 2;
    firstBowl = boardSize / 2 + 1;
    lastBowl = boardSize - 1;
  }  
  
  for(bowl = firstBowl; bowl <= lastBowl; bowl++)
  {
    board[mancala] += board[bowl];
    board[bowl] = 0;
  }
}


DoMove1
/***
StateOfGame DoMove()
Drops the specified stones and cleans up the board 
if the game is over.
***/

inline StateOfGame DoMove1(
  long board[],
  const long boardSize,
  long bowlPlayed,
  long directionPlayed
)
{
  Boolean getToPlayAgain;

  getToPlayAgain = DropStones1(board, boardSize,
            bowlPlayed, directionPlayed);

  if (FirstSideEmpty(board, boardSize / 2)) {
    RemainingToMancala(board, boardSize, false);
    return kGameOver;
  }
  
  if (SecondSideEmpty(board, boardSize)) {
    RemainingToMancala(board, boardSize, true);
    return kGameOver;
  }
  
  if (getToPlayAgain)
    return kPlayAgain;
  else
    return kDefault;
}

DoMove2
inline StateOfGame DoMove2(
  long board[],
  const long boardSize,
  long bowlPlayed,
  long directionPlayed
)
{
  Boolean getToPlayAgain;
  
  getToPlayAgain = DropStones2(board, boardSize,
            bowlPlayed, directionPlayed);

  if (FirstSideEmpty(board, boardSize / 2)) {
    RemainingToMancala(board, boardSize, false);
    return kGameOver;
  }
  
  if (SecondSideEmpty(board, boardSize)) {
    RemainingToMancala(board, boardSize, true);
    return kGameOver;
  }
  
  if (getToPlayAgain)
    return kPlayAgain;
  else
    return kDefault;
}

ClaimingVictory
/* Boolean ClaimingVictory()
  Only called before returning from Mancala
  Does not clean up the board
*/
Boolean ClaimingVictory(
  long board[],
  const long boardSize,
  const Boolean playerOne
)
{
  long bowl;
  long sum = 0;
  long halfBoardSize = boardSize / 2;
  
  if (FirstSideEmpty(board, halfBoardSize))
  {
    for (bowl = halfBoardSize + 1;
        bowl < boardSize; bowl++)
      sum += board[bowl];
    if (playerOne)
      return board[0] > (sum + board[halfBoardSize]);
    else
      return board[0] < (sum + board[halfBoardSize]);
  }
  if (SecondSideEmpty(board, boardSize))
  {
    for (bowl = 1; bowl < halfBoardSize; bowl++)
      sum += board[bowl];
    if (playerOne)
      return (board[0] + sum) > board[halfBoardSize];
    else
      return (board[0] + sum) < board[halfBoardSize];
  }
  return false;
}
 

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1Password is a password manager that uniquely brings you both security and convenience. It is the only program that provides anti-phishing protection and goes beyond password management by adding Web... Read more
Vivaldi 1.9.818.44 - An advanced browser...
Vivaldi is a browser for our friends. In 1994, two programmers started working on a web browser. Our idea was to make a really fast browser, capable of running on limited hardware, keeping in mind... Read more
Vivaldi 1.9.818.44 - An advanced browser...
Vivaldi is a browser for our friends. In 1994, two programmers started working on a web browser. Our idea was to make a really fast browser, capable of running on limited hardware, keeping in mind... Read more
Skim 1.4.29 - PDF reader and note-taker...
Skim is a PDF reader and note-taker for OS X. It is designed to help you read and annotate scientific papers in PDF, but is also great for viewing any PDF file. Skim includes many features and has a... Read more
1Password 6.7.1 - Powerful password mana...
1Password is a password manager that uniquely brings you both security and convenience. It is the only program that provides anti-phishing protection and goes beyond password management by adding Web... Read more
FontExplorer X Pro 6.0.2 - Font manageme...
FontExplorer X Pro is optimized for professional use; it's the solution that gives you the power you need to manage all your fonts. Now you can more easily manage, activate and organize your... Read more
VOX 2.8.24 - Music player that supports...
VOX just sounds better! The beauty is in its simplicity, yet behind the minimal exterior lies a powerful music player with a ton of features and support for all audio formats you should ever need.... Read more

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Fire Emblem Heroes event announces new m...
As reported yesterday, Nintendo was gearing up a live press event for their popular mobile game,Fire Emblem Heroes. While the stream revealed a lot of new things, the event was entirely in Japanese. Luckily we have a rundown of what was announced... | Read more »
Best games we played this week
Another week, another slate of new mobile games. Although there weren't as many big name releases as last week, there were plenty of unique video game titles that came out that's sure to keep you interested over the weekend. Everything from classic... | Read more »
Olli by Tinrocket (Photography)
Olli by Tinrocket 1.0 Device: iOS iPhone Category: Photography Price: $2.99, Version: 1.0 (iTunes) Description: Get drawn in with Olli by TinrocketOlli instantly turns your everyday moments into hand-drawn art and animations. • Watch... | Read more »
Penarium (Games)
Penarium 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: | Read more »
Fire Emblem Heroes is way more profitabl...
Profits for Nintendo's mobile game Fire Emblem Heroes are apparently impressive enough to beat out other Nintendo titles likeSuper Mario Run, despite having 10 times fewer downloads. [Read more] | Read more »
Classic series Robot Unicorn Attack 3 no...
The classic Adult Swim browser game, Robot Unicorn Attack, branched off into a series of popular mobile games. Now, the latest entry into the series, Robot Unicorn Attack 3, is available for iOS and Android mobile devices. [Read more] | Read more »
Sudoku Sweeper (Games)
Sudoku Sweeper 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: A minimalist mashup of Minesweeper and Sudoku. Logic puzzle perfection. Every row, column and zone contains a bomb and one of... | Read more »
Under Leaves (Games)
Under Leaves 1.0.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.0 (iTunes) Description: Journey into the forest, the jungle or the depths of the deep blue sea. Find chestnuts for the pigs, a caterpillar for the... | Read more »
Ninja Pizza Girl (Games)
Ninja Pizza Girl 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: In the not-so-distant future, rampart traffic congestion has resulted in only one way to deliver pizzas across town in thirty... | Read more »
SCRAP (Games)
SCRAP 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: That day, for no apparent reason, SCRAP decided to wake up and run. He had to, because his activation was a mistake the "Factory" could... | Read more »

Price Scanner via MacPrices.net

15-inch 2.7GHz Space Gray Touch Bar MacBook P...
B&H Photo has the 15″ 2.7GHz Space Gray Touch Bar MacBook Pro in stock today and on sale for $2599…$200 off MSRP. Shipping is free, and B&H charges NY & NJ sales tax only: - 15″ 2.7GHz... Read more
13-inch 2.9GHz/256GB Space Gray Touch Bar Mac...
B&H Photo has the 13″ 2.9GHz/256GB Space Gray Touch Bar MacBook Pro in stock today and on sale for $150 off MSRP including free shipping plus NY & NJ sales tax only: - 13″ 2.9GHz/256GB Touch... Read more
21-inch iMacs on sale for up to $151 off MSRP
B&H Photo has 21″ iMacs on sale for up to $151 off MSRP, each including free shipping plus NY sales tax only: - 21″ 3.1GHz iMac 4K: $1348 $151 off MSRP - 21″ 2.8GHz iMac: $1199.99 $100 off MSRP... Read more
Weekend deal: Up to $420 off new MacBook Pros...
Apple has Certified Refurbished 2016 15″ and 13″ MacBook Pros available for $230 to $420 off original MSRP. An Apple one-year warranty is included with each model, and shipping is free: - 15″ 2.6GHz... Read more
Price drop: 15-inch 2.2GHz Retina MacBook Pro...
Amazon has dropped their price on 15″ 2.2GHz Retina MacBook Pros (MJLQ2LL/A) to $1709.99 including free shipping. Their price is $290 off MSRP for this model. Note that stock may sell out quickly at... Read more
2.8GHz Mac mini on sale for $899, save $100
B&H Photo has the 2.8GHz Mac mini (model number MGEQ2LL/A) on sale for $899 including free shipping plus NY & NJ sales tax only. Their price is $100 off MSRP. Read more
Check Apple prices on any device with the iTr...
MacPrices is proud to offer readers a free iOS app (iPhones, iPads, & iPod touch) and Android app (Google Play and Amazon App Store) called iTracx, which allows you to glance at today’s lowest... Read more
New System Clock for macOS by B-Eng Now Avail...
Fehraltorf, Switzerland based B-Eng has announced the release and immediate availability of System Clock, the company’s new system monitor and information app developed exclusively for macOS. System... Read more
DEVONtechnologies Celebrates 15th Anniversary...
DEVONtechnologies celebrates its 15th company anniversary with a 30% discount on all its software products from May 1st through 5th, 2017. In spring 2002, DEVONtechnologies opened its website and... Read more
WaterField Designs Invites Customers to Help...
San Francisco based WaterField Designs invites customers and air travelers to participate in developing the next generation in-flight travel case, the Air Porter. Frustrated with limited legroom,... Read more

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Best Buy *Apple* Computing Master - Best Bu...
**501846BR** **Job Title:** Best Buy Apple Computing Master **Location Number:** 001126-South Bay Center-Store **Job Description:** **What does a Best Buy Apple Read more
Consultant or Sr. Consultant, *Apple* Allia...
…improve our business and your clients will be heard.Project Manager, Apple AllianceLocation:San Francisco preferred, open to other locationsLevel:Consultant or Sr. Read more
*Apple* Mac Computer Technician - GeekHampto...
…complex computer issues over the phone and in person? GeekHampton, Long Island's Apple Premium Service Provider, is looking for you! Come work with our crew Read more
*Apple* Mobile Master - Best Buy (United Sta...
**501505BR** **Job Title:** Apple Mobile Master **Location Number:** 000849-Gurnee-Store **Job Description:** **What does a Best Buy Apple Mobile Master do?** At Read more
Best Buy *Apple* Computing Master - Best Bu...
**498428BR** **Job Title:** Best Buy Apple Computing Master **Location Number:** 000293-Rockville-Store **Job Description:** **What does a Best Buy Apple Read more
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