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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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MTR (was MacTheRipper)--the Mac's oldest and smartest DVD-backup app--is now updated to version 5.001 MTR -- the complete toolbox, not a one-trick, point-and-click extractor. MTR is intended for... Read more
LibreOffice 4.4.5.2 - Free, open-source...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
Adobe Lightroom 6.1.1 - Import, develop,...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
File Juicer 4.41 - Extract images, video...
File Juicer is a drag-and-drop can opener and data archaeologist. Its specialty is to find and extract images, video, audio, or text from files which are hard to open in other ways. It finds and... Read more
A Better Finder Rename 9.52 - File, phot...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more
OmniFocus 2.2.3 - GTD task manager with...
OmniFocus helps you manage your tasks the way that you want, freeing you to focus your attention on the things that matter to you most. Capturing tasks and ideas is always a keyboard shortcut away in... Read more
TinkerTool 5.4 - Expanded preference set...
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the... Read more

Cosmonautica (Games)
Cosmonautica 1.1 Device: iOS Universal Category: Games Price: $6.99, Version: 1.1 (iTunes) Description: Cast off! Are you ready for some hilarious adventures in outer space? | Read more »
Rescue humanity from a Demon horde in An...
Angel Stone is Fincon's follow up to the massively successful Hello Hero and is out now on iOS and Android. You play as a member of The Resistance, a group of mighty human warriors who have risen up in defiance of the Demon horde threatening to... | Read more »
Gallery Doctor (Photography)
Gallery Doctor 1.0 Device: iOS iPhone Category: Photography Price: $2.99, Version: 1.0 (iTunes) Description: Free up valuable iCloud and iPhone storage with Gallery Doctor, the only iPhone cleaner that automatically identifies the... | Read more »
You Against Me (Games)
You Against Me 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: A simple game… You. Me. Claim, steal, lock, score, win! | Read more »
Yep, it's True - Angry Birds 2 is O...
The not exactly rumors were true and the birds are back. Angry Birds 2 has come to the App Store and the world will... well I suppose it'll still be the same, but now we have more bird-flinging options! [Read more] | Read more »
You Could Design Your Own Card for Chain...
If you've ever wanted to create your own item, weapon, trap, or even monster for Chainsaw Warrior: Lords of the Night, this is your chance. Auroch Digital is currently holding a contest so that fans can fight to the death (not really) to see which... | Read more »
Bitcoin Billionaire is Going Back in Tim...
If you thought you managed to buy everything there is to buy in Bitcoin Billionaire and make all the money, well you though wrong. Those of you who made it far enough might remember investing in time travel - and it looks like that investment is... | Read more »
Domino Drop (Games)
Domino Drop 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Domino Drop is a delightful new puzzle game with dominos and gravity!Learn how to play it in a minute, master it day by day.Your... | Read more »
OPERATION DRACULA (Games)
OPERATION DRACULA 1.0.1 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0.1 (iTunes) Description: 25% off launch sale!!! 'Could prove to be one of the most accurate representations of the Japanese bullet hell shmup... | Read more »
Race The Sun (Games)
Race The Sun 1.01 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.01 (iTunes) Description: You are a solar craft. The sun is your death timer. Hurtle towards the sunset at breakneck speed in a futile race against time.... | Read more »

Price Scanner via MacPrices.net

Sale! 13-inch MacBook Pros on sale for $100 o...
B&H Photo has 13″ MacBook Pros on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.5GHz/500GB MacBook Pro: $999.99 save $100 - 13″ 2.7GHz/128GB Retina... Read more
Sale! Save $100 on 13-inch MacBook Airs this...
B&H Photo has the 13″ 1.6GHz/128GB MacBook Air on sale for $899.99 including free shipping plus NY tax only. Their price is $100 off MSRP, and it’s the lowest price available for this model.... Read more
Worldwide Tablet Market Decline Continues, Ap...
The worldwide tablet market declined -7.0% year-over-year in the second quarter of 2015 (2Q15) with shipments totaling 44.7 million units according to preliminary data from the International Data... Read more
TP-LINK TL-PA8030P KIT Powerline Featuring Ho...
Consumer and business networking products provider TP-LINK is now shipping its TL-PA8030P KIT AV1200 3-Port Gigabit Passthrough Powerline Starter Kit that expands your home’s network over its... Read more
Apple refurbished iPad Air 2s available for u...
The Apple Store has Apple Certified Refurbished iPad Air 2s available for up to $140 off the price of new models. Apple’s one-year warranty is included with each model, and shipping is free: - 128GB... Read more
Updated Apple iPad Price Trackers
We’ve updated our iPad Air Price Tracker and our iPad mini Price Tracker with the latest information on prices and availability from Apple and other resellers. Read more
Apple refurbished 2014 13-inch 128GB MacBook...
The Apple Store has Apple Certified Refurbished 2014 13″ MacBook Airs available starting at $759. An Apple one-year warranty is included with each MacBook, and shipping is free: - 13″ 1.4GHz/128GB... Read more
Apple’s Education discount saves up to $300 o...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
Save up to $600 with Apple refurbished Mac Pr...
The Apple Store has Apple Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The... Read more
Mac Pros on sale for up to $260 off MSRP
B&H Photo has Mac Pros on sale for up to $260 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2799, $200 off MSRP - 3.5GHz 6-core Mac Pro: $3719.99... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales. Specialist - Retail Customer Service and Sales. Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Online Store UAT Lead - Apple (Unite...
**Job Summary** The Apple Online Store is a fast paced and ever evolving business environment. The User Acceptance Testing (UAT) lead in this organization is able to Read more
*Apple* MAC Support Services Subject Matter...
Title: Apple MAC Support Services Subject Matter Expert Location: Pleasanton, CA Type of position: Temporary Contract for approximately 6 weeks Tasks The tasks for the Read more
Lead Infrastructure Engineer - *Apple* /Mac P...
…of a team * Requires proven problem solving skills Preferred Additional: * Apple Certified System Administrator (ACSA) * Apple Certified Technical Coordinator (ACTC) Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
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