TweetFollow Us on Twitter

Apr 01 Challenge Volume Number: 17 (2001)
Issue Number: 4
Column Tag: Programmer's Challenge

Programmer's Challenge

By Bob Boonstra, Westford, MA

Crossword II

Several years ago we held a Programmers Challenge based on crossword puzzles. So when my son came home from school with an idea for a crossword Challenge, my first thought was that we had been there and done that. The old Challenge required readers to solve a crossword puzzle, fitting the available words into a predefined pattern, without the benefit of clues. My son's problem, to generate a crossword puzzle, is sufficiently different to make a potentially interesting Challenge.

The prototype for the code you should write is:

typedef struct Words {
   char *theWord;      /* null terminated string */
   short value;         /* points value for theWord */
} Words;

typedef struct WordPositions {
   short whichWord;            /* index in Words array of word being placed */
   short row;                     /* row in which the first letter of the word is placed */
   short col;                     /* col in which the first letter of the word is placed */
   short orientation;         /* 0==down, 1==across */
} WordPositions;

long /* numberOfWordPositions */ CrosswordII  (
   short puzzleSize,            /* puzzle has puzzleSize rows and columns */
   const Words words[],      /* words to be used to form the puzzle */
   short numWords,               /* number of words[] available */
   WordPositions positions[]      /* placement of words in puzzle */
);

The homework assignment that inspired this Challenge was from Chemistry class. Students were required to generate a 20x20 crossword puzzle using the names of the first 103 elements from the periodic table. Each word placed had a value equal to the atomic number for that element. So placing the word "lawrencium" earns you 103 points, "molybdenum" is worth only 42, but "lead" is worth 82. The assignment was to generate a crossword puzzle worth as many points as possible.

For the Challenge, we'll generalize the problem to work with an arbitrary list of words and arbitrarily assigned values. The puzzle dimension will be puzzleSize x puzzleSize instead of 20x20. You should decide which words to place where in the puzzle and return your word placements in the positions array, specifying in positions[].whichWord the index in words of the word being placed, the cell in which the first letter of the word is placed in positions[].row and positions[].col, and the direction the word is being placed in positions[].orientation. Your CrosswordII routine should return the number of words placed in the puzzle.

A few constraints: Each of the words will be at least 3 letters long and terminated with a zero byte. Every pair of adjacent letters in the puzzle you form must be part of some word. No word may occur more than once in the puzzle. Words may be placed horizontally or vertically, but not diagonally.

The winner will be the solution that earns the most points. Points will be based on the value of the words you place in your crossword puzzle, minus a penalty of 1% for each minute of execution time. The Challenge prize will be divided between the overall winner and the best scoring entry from a contestant that has not won the Challenge recently.

This will be a native PowerPC Challenge, using the CodeWarrior Pro 6 environment. Solutions may be coded in C, C++, or Pascal. You may provide a solution in Java instead, provided you also provide a test driver equivalent to the C code provided on the web for this problem.

Three Months Ago Winner

Congratulations to Willeke Rieken for winning the January Tetris Challenge. The Tetris Challenge required readers to provide a player for the classic Tetris game. Willeke actually won by default, as his was the only entry. As I've said before, you can't win if you don't play. With this win, Willeke vaults into second place in our Challenge points standings.

Willeke describes his solution as "low tech". The heavy lifting is done in his MovePiece routine, where he determines the position and orientation of the current piece that provides the best fit. His heuristic for best fit takes into consideration the number of unreachable empty spaces created by placing a piece, with special weighting against placements that create "deep pits". The solution does not take advantage of the opportunity to move a piece after it has been dropped, nor does it use the information provided about the next piece to be placed.

Top Contestants...

Listed here are the Top Contestants for the Programmer's Challenge, including everyone who has accumulated 20 or more 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.

Rank Name Points
1. Munter, Ernst 281
2. Rieken, Willeke 85
3. Saxton, Tom 76
4. Maurer, Sebastian 68
5. Boring, Randy 52
6. Shearer, Rob 48
7. Taylor, Jonathan 36
8. Wihlborg, Charles 29

... and the Top Contestants Looking For a Recent Win

Starting this month, in order to give some recognition to other participants in the Challenge, we are also going to list the high scores for contestants who have accumulated points without taking first place in a Challenge. Listed here are all of those contestants who have accumulated 6 or more points during the past two years.

9. Downs, Andrew 12
10. Jones, Dennis 12
11. Day, Mark 10
12. Duga, Brady 10
13. Fazekas, Miklos 10
14. Flowers, Sue 10
15. Sadetsky, Gregory 10
16. Selengut, Jared 10
17. Strout, Joe 10
18. Hala, Ladislav 7
19. Miller, Mike 7
20. Nicolle, Ludovic 7
21. Schotsman, Jan 7
22. Widyyatama, Yudhi 7
23. Heithcock, JG 6

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 Willeke's winning Tetris solution:

tetris.cp
Copyright © 2001
Willeke Rieken
/*
   a piece is dropped at each column and points are given for
   creating empty cells and adding height. points are subtracted
   for fitting in existing holes. the column with the lowest
   score wins. the moves to drop the piece in the winning
   column are placed in an array. in subsequent calls of Tetris
   the next move is returned.
   this is a low tech solution without using the next piece or
   the possibility to move a piece after it dropped. 
*/

#include <stdio.h>
#include <string.h>

#include "Tetris.h"

#define kPieceSize 7
#define kHalfPieceSize 3
#define kMaxBoardSizeSize 256
#define kMaxNrRotations 4

typedef struct PieceInfo {
   long pieceLeft, pieceRight, pieceTop, pieceBottom;
   long nrOfRorations;
} PieceInfo;

static const Piece *gGamePieces;
static MoveType gMovesToDo[(kMaxBoardSizeSize / 2) + 3];
   // (max board size/2) lefts or rights + 2 rotations + drop
static PieceInfo *gPieceInfo;
static long gNrMovesToDo, gMoveNr;
static long gLastPieceIndex, glastNextPieceIndex;
static long gNumRows, gNumCols;
static long gNumPieceTypes, gMaxPieceSize;

PieceFits

static short PieceFits(const Board gameBoard, long *theTopOfPieces,
                                    Piece theActivePiece,
                              long thePieceLeft, long thePieceRight,
                              long thePieceTop, long thePieceBottom,
                                    long theRow, long theCol,
                                    short theMustFitInBoard)
// check if the piece will fit on the board at
// position (theRow,theCol), if theMustFitInBoard then
// the total piece has to be on the board
{
   long   aRowOffset, aColOffset;
   long   aRow, aCol;

   aRowOffset = theRow - thePieceBottom - 1;
   aColOffset = theCol - kHalfPieceSize;
   for (aRow = thePieceTop; aRow <= thePieceBottom; aRow++)
      for (aCol = thePieceLeft; aCol <= thePieceRight; aCol++)
      {
         if (theActivePiece[aRow][aCol])
         {
            if (aRowOffset + aRow < 0)
               if (theMustFitInBoard)
                  return 0;
               else
                  break;
            if (theMustFitInBoard)
               if (aRowOffset + aRow >= 
                           theTopOfPieces[aColOffset + aCol])
                  return 0;
   if (gameBoard[aRowOffset + aRow][aColOffset + aCol] >= 0)
               return 0;
         }
      }
   return 1;
}

RotatePiece90

static void RotatePiece90(Piece theActivePiece,
                                       long *aPieceLeft, long *aPieceRight,
                                       long *aPieceTop, long *aPieceBottom)
// rotates the piece 90° clockwise
{
   Piece   aRotatedPiece;
   long   aRow, aCol;
   
   for (aRow = 0; aRow < kPieceSize; aRow++)
      for (aCol = 0; aCol < kPieceSize; aCol++)
         aRotatedPiece[aCol][kPieceSize - 1 - aRow] =
               theActivePiece[aRow][aCol];
   memcpy(theActivePiece, aRotatedPiece, sizeof(Piece));
         
   aRow = *aPieceLeft;
   *aPieceLeft = kPieceSize - 1 - *aPieceBottom;
   *aPieceBottom = *aPieceRight;
   *aPieceRight = kPieceSize - 1 - *aPieceTop;
   *aPieceTop = aRow;
}

RotatePiece180
static void RotatePiece180(Piece theActivePiece,
                                       long *aPieceLeft, long *aPieceRight,
                                       long *aPieceTop, long *aPieceBottom)
// rotates the piece 180°
{
   Piece   aRotatedPiece;
   long   aRow, aCol;
   
   for (aRow = 0; aRow < kPieceSize; aRow++)
      for (aCol = 0; aCol < kPieceSize; aCol++)
         aRotatedPiece[kPieceSize - 1 - aRow][kPieceSize - 1 - aCol] 
                  =   theActivePiece[aRow][aCol];
   memcpy(theActivePiece, aRotatedPiece, sizeof(Piece));
         
   aRow = *aPieceTop;
   *aPieceTop = kPieceSize - 1 - *aPieceBottom;
   *aPieceBottom = kPieceSize - 1 - aRow;
   aRow = *aPieceLeft;
   *aPieceLeft = kPieceSize - 1 - *aPieceRight;
   *aPieceRight = kPieceSize - 1 - aRow;
}

RotatePiece270
static void RotatePiece270(Piece theActivePiece,
                                       long *aPieceLeft, long *aPieceRight,
                                       long *aPieceTop, long *aPieceBottom)
// rotates the piece 90° counter clockwise
{
   Piece   aRotatedPiece;
   long   aRow, aCol;
   
   for (aRow = 0; aRow < kPieceSize; aRow++)
      for (aCol = 0; aCol < kPieceSize; aCol++)
         aRotatedPiece[kPieceSize - 1 - aCol][aRow] =
               theActivePiece[aRow][aCol];
   memcpy(theActivePiece, aRotatedPiece, sizeof(Piece));
         
   aRow = *aPieceTop;
   *aPieceTop = kPieceSize - 1 - *aPieceRight;
   *aPieceRight = *aPieceBottom;
   *aPieceBottom = kPieceSize - 1 - *aPieceLeft;
   *aPieceLeft = aRow;
}

FindCompletedLines
static void FindCompletedLines(const Board gameBoard,
                                             short theCompletedLines[kPieceSize],
                                             long *theNrCompletedLines,
                                             Piece theActivePiece,
                                             long thePieceLeft, long thePieceRight,
                                             long thePieceTop, long thePieceBottom,
                                             long theRow, long theCol)
// find the lines that are completed and will disappear after the piece dropped
{
   long   aRowOffset, aColOffset;
   long   aRow, aCol;

   aRowOffset = theRow - thePieceBottom - 1;
   aColOffset = theCol - kHalfPieceSize;

   for (aRow = 0; aRow < kPieceSize; aRow++)
      theCompletedLines[aRow] = 0;
   *theNrCompletedLines = 0;
      
   for (aRow = thePieceTop; aRow <= thePieceBottom; aRow++)
   {
      theCompletedLines[aRow] = 1;
      for (aCol = thePieceLeft; aCol <= thePieceRight; aCol++)
         if ((!theActivePiece[aRow][aCol]) &&
               (gameBoard[aRowOffset + aRow][aColOffset + aCol] == -1))
         {
            theCompletedLines[aRow] = 0;
            break;
         }
      if (theCompletedLines[aRow])
      {
         for (aCol = 0; aCol < aColOffset + thePieceLeft; aCol++)
            if (gameBoard[aRowOffset + aRow][aCol] == -1)
            {
               theCompletedLines[aRow] = 0;
               break;
            }
      }
      if (theCompletedLines[aRow])
      {
         for (aCol = aColOffset + thePieceRight + 1; 
                     aCol < gNumCols; aCol++)
            if (gameBoard[aRowOffset + aRow][aCol] == -1)
            {
               theCompletedLines[aRow] = 0;
               break;
            }
      }
      if (theCompletedLines[aRow])
         (*theNrCompletedLines)++;
   }
}

CountEmptySpaces
static long CountEmptySpaces(long *theTopOfPieces,
                                             short theCompletedLines[kPieceSize],
                                             Piece theActivePiece,
                                             long thePieceLeft, long thePieceRight,
                                             long thePieceTop, long thePieceBottom,
                                             long theRow, long theCol)
// count the empty cells as a result of the piece being dropped
// at theCol. don't include the empty cells that will be part
// of the big space at the top after de completed lines are removed
{
   long   aRowOffset, aColOffset;
   long   aRow, aCol, aNrOfEmptySpaces;

   aRowOffset = theRow - thePieceBottom - 1;
   aColOffset = theCol - kHalfPieceSize;
   aNrOfEmptySpaces = 0;
   for (aCol = thePieceLeft; aCol <= thePieceRight; aCol++)
   {
      short   aPieceInColumn = 0;
      
      for (aRow = thePieceTop; aRow <= thePieceBottom; aRow++)
         if (theActivePiece[aRow][aCol] && 
                     (!theCompletedLines[aRow]))
         {
            aPieceInColumn = 1;
            break;
         }
      if (aPieceInColumn)
      {
         aRow = thePieceTop;
         while ((!theActivePiece[aRow][aCol]) && 
                           (aRow <= thePieceBottom))
            aRow++;
         while ((aRow + aRowOffset < 
                           theTopOfPieces[aColOffset + aCol]) &&
                     (aRow <= thePieceBottom))
         {
            if (!theActivePiece[aRow][aCol])
               aNrOfEmptySpaces++;
            aRow++;
         }
         if (aRow + aRowOffset < theTopOfPieces[aColOffset + aCol])
            if ((theTopOfPieces[aColOffset + aCol] - aRow - aRowOffset) 
                              > gMaxPieceSize)
               aNrOfEmptySpaces += gMaxPieceSize;
            else
               aNrOfEmptySpaces += (theTopOfPieces[aColOffset + aCol] - 
                                                            aRow - aRowOffset);
      }
   }
   return aNrOfEmptySpaces;
}

CountTouches
static long CountTouches(const Board gameBoard,
                                    long *theTopOfPieces, Piece theActivePiece,
                                    long thePieceLeft, long thePieceRight,
                                    long thePieceTop, long thePieceBottom,
                                    long theRow, long theCol)
// count at how many cells the piece will touch the pieces on
// the board, subtract points for creating deep pits
{
   long   aRowOffset, aColOffset;
   long   aRow, aCol, aNrOfTouches;

   aRowOffset = theRow - thePieceBottom - 1;
   aColOffset = theCol - kHalfPieceSize;
   aNrOfTouches = 0;
   for (aRow = thePieceTop; aRow <= thePieceBottom; aRow++)
      for (aCol = thePieceLeft; aCol <= thePieceRight; aCol++)
         if (theActivePiece[aRow][aCol])
         {
            // touches on the left
            if (aColOffset + aCol == 0)
               aNrOfTouches++;
            else
               if (((aCol == thePieceLeft) ||
                        (!theActivePiece[aRow][aCol - 1])) &&
                     (gameBoard[aRowOffset + aRow][aColOffset + aCol - 1] 
                                                != -1))
                  aNrOfTouches++;
            // touches on the right
            if (aColOffset + aCol == gNumCols - 1)
               aNrOfTouches++;
            else
               if (((aCol == thePieceRight) ||
                        (!theActivePiece[aRow][aCol + 1])) &&
                     (gameBoard[aRowOffset + aRow][aColOffset + aCol + 1] 
                                                != -1))
                  aNrOfTouches++;
            // touches on the bottom
            if (aRowOffset + aRow == gNumRows - 1)
               aNrOfTouches++;
            else
               if (((aRow == thePieceBottom) ||
                        (!theActivePiece[aRow + 1][aCol])) &&
                     (gameBoard[aRowOffset + aRow + 1][aColOffset + aCol] 
                                                != -1))
                  aNrOfTouches++;
         }
   // check for deep pits
   if ((aColOffset + thePieceLeft > 0) &&
      (theTopOfPieces[aColOffset + thePieceLeft - 1] >
            aRowOffset + thePieceBottom + 1))
   {
      aNrOfTouches -= 
            ((theTopOfPieces[aColOffset + thePieceLeft - 1]) -
               (aRowOffset + thePieceTop + 1));
      aRow = thePieceTop;
      while (!theActivePiece[aRow][thePieceLeft])
      {
         aRow-;
         aNrOfTouches++;
      }
   }
   if ((aColOffset + thePieceRight < gNumCols - 1) &&
      (theTopOfPieces[aColOffset + thePieceRight + 1] >
            aRowOffset + thePieceBottom + 1))
   {
      aNrOfTouches -= ((theTopOfPieces[aColOffset + 
                                          thePieceRight + 1]) -
                                          (aRowOffset + thePieceTop + 1));
      aRow = thePieceTop;
      while (!theActivePiece[aRow][thePieceRight])
      {
         aRow-;
         aNrOfTouches++;
      }
   }
   return aNrOfTouches;
}

ValidMove
static short ValidMove(const Board gameBoard,
                                 short activePieceTypeIndex,
                                 long *theTopOfPieces, long theTopTopOfPieces,
                                 long theCol, long theRotation)
// check if the piece can reach its column without
// colliding with pieces on the board
{
   long   aCol, aRow, aNrMovesToDo;
   Piece   anActivePiece;
   long   aPieceLeft, aPieceRight, aPieceTop, aPieceBottom;

   memcpy(anActivePiece, gGamePieces[activePieceTypeIndex], 
                              sizeof(Piece));
   aPieceLeft = gPieceInfo[activePieceTypeIndex].pieceLeft;
   aPieceRight = gPieceInfo[activePieceTypeIndex].pieceRight;
   aPieceTop = gPieceInfo[activePieceTypeIndex].pieceTop;
   aPieceBottom = gPieceInfo[activePieceTypeIndex].pieceBottom;

   aRow = 1 - aPieceBottom;

   // count moves
   aNrMovesToDo = 0;
   switch (theRotation)
   {
      case 0:
         break;
      case 1:
         aNrMovesToDo++;
         break;
      case 2:
         aNrMovesToDo++;
         aNrMovesToDo++;
         break;
      case 3:
         aNrMovesToDo++;
         break;
   }
   if (theCol > gNumCols / 2)
      aNrMovesToDo += theCol - gNumCols / 2;
   else
      aNrMovesToDo += gNumCols / 2 - theCol;
      
   // check if the piece can move without hitting pieces on the board
   if (aNrMovesToDo >= theTopTopOfPieces)
   {
      switch (theRotation)
      {
         case 0:
            break;
         case 1:
            RotatePiece90(anActivePiece,
                                 &aPieceLeft, &aPieceRight,
                                 &aPieceTop, &aPieceBottom);
            aRow++;
            break;
         case 2:
            RotatePiece180(anActivePiece, &aPieceLeft,
                                 &aPieceRight, &aPieceTop,
                                 &aPieceBottom);
            aRow++;
            aRow++;
            break;
         case 3:
            RotatePiece270(anActivePiece,
                                 &aPieceLeft, &aPieceRight,
                                 &aPieceTop, &aPieceBottom);
            aRow++;
            break;
      }
      aRow += aPieceBottom;
      for (aCol = gNumCols / 2 + 1; aCol < theCol; aCol++)
         if (!PieceFits(gameBoard, theTopOfPieces, anActivePiece,
                              aPieceLeft, aPieceRight, aPieceTop, aPieceBottom,
                              aRow + (aCol - (gNumCols / 2 + 1)), aCol, 0))
            return 0;
      for (aCol = gNumCols / 2 - 1; aCol > theCol; aCol-)
         if (!PieceFits(gameBoard, theTopOfPieces, anActivePiece,
                              aPieceLeft, aPieceRight, aPieceTop, aPieceBottom,
                              aRow + ((gNumCols / 2 - 1) - aCol), aCol, 0))
            return 0;
   }
   return 1;
}

MovePiece
static void MovePiece(const Board gameBoard,
                                 short activePieceTypeIndex)
// determine the column for the piece and prepare the moves
{
   Piece   anActivePiece;
   long   aPieceLeft, aPieceRight, aPieceTop, aPieceBottom;
   long   aRow, aCol, aRotation;
   long   aTopOfPieces[kMaxBoardSizeSize];
   long   aBottomTopRow, aTopTopRow;
   long   aColScore[kMaxNrRotations][kMaxBoardSizeSize];
   long   aBestScore, aBestCol, aBestRotation;
   long   anExtraScore, aNrCompletedLines;
   short   aCompletedLines[kPieceSize];
   short   aValidMove;

   memcpy(anActivePiece, gGamePieces[activePieceTypeIndex],
             sizeof(Piece));
   
   aPieceLeft = gPieceInfo[activePieceTypeIndex].pieceLeft;
   aPieceRight = gPieceInfo[activePieceTypeIndex].pieceRight;
   aPieceTop = gPieceInfo[activePieceTypeIndex].pieceTop;
   aPieceBottom = gPieceInfo[activePieceTypeIndex].pieceBottom;

   // find top of pieces in board
   aBottomTopRow = 0;
   aTopTopRow = gNumCols;
   for (aCol = 0; aCol < gNumCols; aCol++)
   {
      aRow = 0;
      while ((aRow < gNumRows) &&
                  (gameBoard[aRow][aCol] == -1)) aRow++;
      aTopOfPieces[aCol] = aRow;
      if (aBottomTopRow < aRow)
         aBottomTopRow = aRow;
      if (aTopTopRow > aRow)
         aTopTopRow = aRow;
   }

   // find where the piece fits best
   for (aRotation = 0;
            aRotation < gPieceInfo[activePieceTypeIndex].nrOfRorations;
            aRotation++)
   {
      for (aCol = 0; aCol < gNumCols; aCol++)
      {
         aColScore[aRotation][aCol] = 1000000;
         if ((aCol >= kHalfPieceSize - aPieceLeft) &&
               (aCol < gNumCols - aPieceRight + kHalfPieceSize))
         {
            aRow = aTopOfPieces[aCol] + kPieceSize - 1;
            if (aRow > aBottomTopRow)
               aRow = aBottomTopRow;
      while ((!PieceFits(gameBoard, aTopOfPieces, anActivePiece,
                  aPieceLeft, aPieceRight, aPieceTop, aPieceBottom,
                              aRow, aCol, 1)) &&
                  (aRow >= 0))
               aRow-;
            if (aRow > (aPieceBottom - aPieceTop - 1))
            {
               aColScore[aRotation][aCol] =
                  ((aBottomTopRow - aRow) + 
                  (aPieceBottom - aPieceTop)) * 2;
               FindCompletedLines(gameBoard, aCompletedLines,
                        &aNrCompletedLines, anActivePiece,
                  aPieceLeft, aPieceRight, aPieceTop, aPieceBottom,
                        aRow, aCol);
               anExtraScore = CountEmptySpaces(aTopOfPieces,
                        aCompletedLines, anActivePiece,
                  aPieceLeft, aPieceRight, aPieceTop, aPieceBottom,
                        aRow, aCol);
               aColScore[aRotation][aCol] += anExtraScore * 5;
               anExtraScore = CountTouches(gameBoard,
                     aTopOfPieces, anActivePiece,
               aPieceLeft, aPieceRight, aPieceTop, aPieceBottom,
                        aRow, aCol);
               aColScore[aRotation][aCol] -= anExtraScore;
            }
         }
      }
      RotatePiece90(anActivePiece,
                  &aPieceLeft, &aPieceRight, &aPieceTop, &aPieceBottom);
   }
   aBestCol = 0;
   aBestRotation = 0;
   aValidMove = 0;
   while (!aValidMove)
   {
      aBestScore = 1000000;
      for (aRotation = 0;
            aRotation < gPieceInfo[activePieceTypeIndex].nrOfRorations;
            aRotation++)
         for (aCol = 0; aCol < gNumCols; aCol++)
            if (aColScore[aRotation][aCol] < aBestScore)
            {
               aBestScore = aColScore[aRotation][aCol];
               aBestCol = aCol;
               aBestRotation = aRotation;
            }
      if (aBestScore < 1000000)   // found valid move
      {
         if (ValidMove(gameBoard, activePieceTypeIndex,
                  aTopOfPieces, aTopTopRow, aBestCol, aBestRotation))
            aValidMove = 1;
         else
            aColScore[aBestRotation][aBestCol] = 1000000;
      }
      else
      {
         // no valid moves, give up
         aBestCol = gNumCols / 2;
         aBestRotation = 0;
         aValidMove = 1;
      }
   }
   
   // prepare moves
   gNrMovesToDo = 0;
   switch (aBestRotation)
   {
      case 1:
         gMovesToDo[gNrMovesToDo] = kRotateClockwise;
         gNrMovesToDo++;
         break;
      case 2:
         gMovesToDo[gNrMovesToDo] = kRotateClockwise;
         gNrMovesToDo++;
         gMovesToDo[gNrMovesToDo] = kRotateClockwise;
         gNrMovesToDo++;
         break;
      case 3:
         gMovesToDo[gNrMovesToDo] = kRotateCounterClockwise;
         gNrMovesToDo++;
         break;
   }
   if (aBestCol > gNumCols / 2)
      for (aCol = gNumCols / 2; aCol < aBestCol; aCol++)
      {
         gMovesToDo[gNrMovesToDo] = kMoveRight;
         gNrMovesToDo++;
      }
   else
      for (aCol = aBestCol; aCol < gNumCols / 2; aCol++)
      {
         gMovesToDo[gNrMovesToDo] = kMoveLeft;
         gNrMovesToDo++;
      }
   gMovesToDo[gNrMovesToDo] = kDrop;
   gNrMovesToDo++;
   gMovesToDo[gNrMovesToDo] = kNoMove;
   gNrMovesToDo++;
}

GetPieceInfo
static void GetPieceInfo()
// determine the bounds of the piece and if rotating
// the piece results in the same piece 
{
   long   i;

   for (i = 0; i < gNumPieceTypes; i++)
   {
      long   aPieceLeft = kPieceSize - 1, aPieceRight = 0;
      long   aPieceTop = kPieceSize - 1, aPieceBottom = 0;
      Piece   anActivePiece;
      long   aRow, aCol, aRowOffset, aColOffset;
      short   aPiecesMatch;

      memcpy(anActivePiece, gGamePieces[i], sizeof(Piece));
      for (aRow = 0; aRow < kPieceSize; aRow++)
         for (aCol = 0; aCol < kPieceSize; aCol++)
            if (anActivePiece[aRow][aCol])
            {
               if (aRow < aPieceTop)
                  aPieceTop = aRow;
               if (aRow > aPieceBottom)
                  aPieceBottom = aRow;
               if (aCol < aPieceLeft)
                  aPieceLeft = aCol;
               if (aCol > aPieceRight)
                  aPieceRight = aCol;
            }
      gPieceInfo[i].pieceLeft = aPieceLeft;
      gPieceInfo[i].pieceRight = aPieceRight;
      gPieceInfo[i].pieceTop = aPieceTop;
      gPieceInfo[i].pieceBottom = aPieceBottom;
      
      if (aPieceRight - aPieceLeft > gMaxPieceSize)
         gMaxPieceSize = aPieceRight - aPieceLeft;
      if (aPieceBottom - aPieceTop > gMaxPieceSize)
         gMaxPieceSize = aPieceBottom - aPieceTop;
      
      gPieceInfo[i].nrOfRorations = kMaxNrRotations;

      RotatePiece90(anActivePiece,
                  &aPieceLeft, &aPieceRight, &aPieceTop, &aPieceBottom);
      if ((aPieceRight - aPieceLeft) == (aPieceBottom - aPieceTop))
      {
         aPiecesMatch = 1;
         aRowOffset = gPieceInfo[i].pieceTop - aPieceTop;
         aColOffset = gPieceInfo[i].pieceLeft - aPieceLeft;
         for (aRow = aPieceTop; aRow <= aPieceBottom; aRow++)
            for (aCol = aPieceLeft; aCol <= aPieceRight; aCol++)
               if ((anActivePiece[aRow][aCol] &&
                        !gGamePieces[i][aRow + aRowOffset][aCol + 
                                    aColOffset]) ||
                     (!anActivePiece[aRow][aCol] &&
                        gGamePieces[i][aRow + 
                              aRowOffset][aCol + aColOffset]))
                  aPiecesMatch = 0;
         if (aPiecesMatch)
            gPieceInfo[i].nrOfRorations = 1;
      }
      if (gPieceInfo[i].nrOfRorations == kMaxNrRotations)
      {
         RotatePiece90(anActivePiece,
                  &aPieceLeft, &aPieceRight, &aPieceTop, &aPieceBottom);
         aPiecesMatch = 1;
         aRowOffset = gPieceInfo[i].pieceTop - aPieceTop;
         aColOffset = gPieceInfo[i].pieceLeft - aPieceLeft;
         for (aRow = aPieceTop; aRow <= aPieceBottom; aRow++)
            for (aCol = aPieceLeft; aCol <= aPieceRight; aCol++)
               if ((anActivePiece[aRow][aCol] &&
                        !gGamePieces[i][aRow + 
                                       aRowOffset][aCol + aColOffset]) ||
                     (!anActivePiece[aRow][aCol] &&
                        gGamePieces[i][aRow + 
                                       aRowOffset][aCol + aColOffset]))
                  aPiecesMatch = 0;
         if (aPiecesMatch)
            gPieceInfo[i].nrOfRorations = 2;
      }
   }
}

InitTetris
void InitTetris(
  short boardWidth,            /* width of board in cells */
  short boardHeight,         /* height of board in cells */
  short numPieceTypes,      /* number of types of pieces */
  const Piece gamePieces[],   /* pieces to play */
  long timeToPlay               /* game time, in milliseconds */
) {
   gNumRows = boardHeight;
   gNumCols = boardWidth;
   gNumPieceTypes = numPieceTypes;
   gGamePieces = gamePieces;
   gNrMovesToDo = 0;
   gMoveNr = 0;
   gLastPieceIndex = -1;
   glastNextPieceIndex = -1;
   gPieceInfo = new PieceInfo[gNumPieceTypes];
   gMaxPieceSize = 0;
   GetPieceInfo();
   gMaxPieceSize++;
}

Tetris
MoveType /* move active piece */ Tetris(
  const Board gameBoard,      
  /* current state of the game board,
     bottom row is [boardHeight-1], left column is [0] */
  short activePieceTypeIndex,   /* index into gamePieces of active piece */
  short nextPieceTypeIndex,      /* index into gamePieces of next piece */
  long pointsEarned,                     /* number of points earned thus far */
  long timeToGo                              /* time remaining, in milliseconds */
) {
   // try to detect a new piece,
   // will fail when a piece appears three times in a row
   if ((gLastPieceIndex != activePieceTypeIndex) ||
         (glastNextPieceIndex != nextPieceTypeIndex))
      gMoveNr = gNrMovesToDo;
   gLastPieceIndex = activePieceTypeIndex;
   glastNextPieceIndex = nextPieceTypeIndex;

   if (gMoveNr >= gNrMovesToDo)
   {
      // calculate the moves for a new piece
      MovePiece(gameBoard, activePieceTypeIndex);
      gMoveNr = 0;
   }
   // return next move
   return gMovesToDo[gMoveNr++];
}

TermTetris
void TermTetris(void) {
   delete[] gPieceInfo;
}
 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Cyberduck 4.7.1 - FTP and SFTP browser....
Cyberduck is a robust FTP/FTP-TLS/SFTP browser for the Mac whose lack of visual clutter and cleverly intuitive features make it easy to use. Support for external editors and system technologies such... Read more
PDFpen 7.2 - Edit and annotate PDFs with...
We're also offering PDFpenPro for 30% off! PDFpen allows users to easily edit PDF's. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even... Read more
Skype 7.9.746 - Voice-over-internet phon...
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
Apple GarageBand 10.1 - Complete recordi...
The new GarageBand is a whole music creation studio right inside your Mac -- complete with keyboard, synths, orchestral and percussion instruments, presets for guitar and voice, an entirely... Read more
Duplicate Annihilator 5.7.7 - Find and d...
Duplicate Annihilator takes on the time-consuming task of comparing the images in your iPhoto library using effective algorithms to make sure that no duplicate escapes. Duplicate Annihilator... Read more
OS X Server 4.1.3 - For OS X 10.10 Yosem...
Designed for OS X and iOS devices, OS X Server makes it easy to share files, schedule meetings, synchronize contacts, develop software, host your own website, publish wikis, configure Mac, iPhone,... Read more
Firefox 39.0 - Fast, safe Web browser. (...
Firefox offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals and casual... Read more
pwSafe 4.1 - Secure password management...
pwSafe provides simple and secure password management across devices and computers. pwSafe uses iCloud to keep your password databases backed-up and synced between Macs and iOS devices. It is... Read more
Kodi 15.0.rc1 - Powerful media center to...
Kodi (was XBMC) is an award-winning free and open-source (GPL) software media player and entertainment hub that can be installed on Linux, OS X, Windows, iOS, and Android, featuring a 10-foot user... Read more
Coda 2.5.11 - One-window Web development...
Coda is a powerful Web editor that puts everything in one place. An editor. Terminal. CSS. Files. With Coda 2, we went beyond expectations. With loads of new, much-requested features, a few surprises... Read more

This Week at 148Apps: June 29-July 3, 20...
Into July With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above the... | Read more »
Sonic Runners Guide
Despite its flaws, Sonic Runners' platforming action is actually quite fun. Though it can be a little more complicated than old-school Sonic games. Here's how to make sure you're up to speed when jumping in. [Read more] | Read more »
Rage of Bahamut is Giving Almost All of...
The App Store isn't what it used to be back in 2012, so it's not unexpected to see some games changing their structures with the times. Now we can add Rage of Bahamut to that list with the recent announcement that the game is severely cutting back... | Read more »
Adventures of Pip (Games)
Adventures of Pip 1.0 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: ** ONE WEEK ONLY — 66% OFF! *** “Adventures of Pip is a delightful little platformer full of charm, challenge and impeccable... | Read more »
Divide By Sheep - Tips, Tricks, and Stre...
Who would have thought splitting up sheep could be so involved? Anyone who’s played Divide by Sheep, that’s who! While we’re not about to give you complete solutions to everything (because that’s just cheating), we will happily give you some... | Read more »
NaturalMotion and Zynga Have Started Tea...
An official sequel to 2012's CSR Racing is officially on the way, with Zynga and NaturalMotion releasing a short teaser trailer to get everyone excited. Well, as excited as one can get from a trailer with no gameplay footage, anyway. [Read more] | Read more »
Grab a Friend and Pick up Overkill 3, Be...
Overkill 3 is a pretty enjoyable third-person shooter that was sort of begging for some online multiplayer. Fortunately the begging can stop, because its newest update has added an online co-op mode. [Read more] | Read more »
Scanner Pro's Newest Update Adds Au...
Scanner Pro is one of the most popular document scanning apps on iOS, thanks in no small part to its near-constant updates, I'm sure. Now we're up to update number six, and it adds some pretty handy new features. [Read more] | Read more »
Heroki (Games)
Heroki 1.0 Device: iOS Universal Category: Games Price: $7.99, Version: 1.0 (iTunes) Description: CLEAR THE SKIES FOR A NEW HERO!The peaceful sky village of Levantia is in danger! The dastardly Dr. N. Forchin and his accomplice,... | Read more »
Wars of the Roses (Games)
Wars of the Roses 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: | Read more »

Price Scanner via MacPrices.net

Apple refurbished Mac minis available startin...
The Apple Store has Apple Certified Refurbished 2014 Mac minis available starting at $419. Apple’s one-year warranty is included with each mini, and shipping is free: - 1.4GHz Mac mini: $419 $80 off... Read more
College Student Deals: Additional $100 off Ma...
Take an additional $100 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through August 8, 2015. Anyone with a valid .EDU email address can take... Read more
Sky Atlas Star Walk 2 App For iPhone And iPa...
Vito Technology, developer of educational apps for Android and iOS, is for a limited time offering free of charge their Star Walk 2, the next generation of the company’s best-selling stargazing guide... Read more
13-inch 1.6GHz MacBook Air on sale for $849,...
Amazon has the 2015 13″ 1.6GHz/128GB MacBook Air on sale for $849.99 including free shipping. Their price is $150 off MSRP, and it’s the lowest price available for this model. Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
Adorama has the 13-inch 2.5GHz MacBook Pro on sale for $999 including free shipping plus NY & NJ sales tax only. Their price is $100 off MSRP. Read more
Updated Mac Price Trackers
We’ve updated our Mac Price Trackers with the latest information on prices, bundles, and availability on systems from Apple’s authorized internet/catalog resellers: - 15″ MacBook Pros - 13″ MacBook... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has new 2015 15″ Retina MacBook Pros on sale for up to $225 off MSRP including free shipping plus NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1819 $180 off - 15″ 2.5GHz Retina... Read more
RamDisk4Mac App Helps Run Your Mac Faster And...
Ever use a RAM disk? If you’ve come to the Mac in the OS X era, likely not. The Classic Mac OS had a RAM disk function built-in, but that was dropped in the conversion to OS X. What is a RAM disk?... Read more
13-inch 1.6GHz MacBook Air on sale for $849,...
Best Buy has the 2015 13″ 1.6GHz/128GB MacBook Air on sale for $849.99 on their online store this weekend. Choose free shipping or free local store pickup (if available). Sale price for online orders... Read more
Apple Refurbished iMacs available for up to $...
The Apple Store has Apple Certified Refurbished iMacs available for up to $380 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $1949 $... Read more

Jobs Board

*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
Senior Payments Security Manager - *Apple*...
**Job Summary** Apple , Inc. is looking for a highly motivated, innovative and hands-on senior payments security manager to join the Apple Pay security team. You will Read more
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
Sr. Payment Program Manager, *Apple* Pay -...
**Job Summary** Apple Pay is an exciting environment and a…devices in a simple, private and secure way. The Apple Pay Team is looking for an experienced Senior Read more
Project Manager - *Apple* Pay Security - Ap...
**Job Summary** The Apple Pay Security team is seeking a highly organized, results-driven Project Manager to drive the development of Apple Pay Security. If you are Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.