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;
}
 
AAPL
$97.02
Apple Inc.
-0.17
MSFT
$44.46
Microsoft Corpora
-0.41
GOOG
$593.93
Google Inc.
-2.05

MacTech Search:
Community Search:

Software Updates via MacUpdate

Audio Hijack Pro 2.11.0 - Record and enh...
Audio Hijack Pro drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio with Audio Hijack... Read more
Intermission 1.1.1 - Pause and rewind li...
Intermission allows you to pause and rewind live audio from any application on your Mac. Intermission will buffer up to 3 hours of audio, allowing users to skip through any assortment of audio... Read more
Airfoil 4.8.7 - Send audio from any app...
Airfoil allows you to send any audio to AirPort Express units, Apple TVs, and even other Macs and PCs, all in sync! It's your audio - everywhere. With Airfoil you can take audio from any... Read more
Microsoft Remote Desktop 8.0.8 - Connect...
With Microsoft Remote Desktop, you can connect to a remote PC and your work resources from almost anywhere. Experience the power of Windows with RemoteFX in a Remote Desktop client designed to help... Read more
xACT 2.30 - Audio compression toolkit. (...
xACT stands for X Aaudio Compression Toolkit, an application that encodes and decodes FLAC, SHN, Monkey’s Audio, TTA, Wavpack, and Apple Lossless files. It also can encode these formats to MP3, AAC... Read more
Firefox 31.0 - Fast, safe Web browser. (...
Firefox for Mac 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... Read more
Little Snitch 3.3.3 - Alerts you to outg...
Little Snitch gives you control over your private outgoing data. Track background activityAs soon as your computer connects to the Internet, applications often have permission to send any... Read more
Thunderbird 31.0 - Email client from Moz...
As of July 2012, Thunderbird has transitioned to a new governance model, with new features being developed by the broader free software and open source community, and security fixes and improvements... Read more
Together 3.2 - Store and organize all of...
Together helps you organize your Mac, giving you the ability to store, edit and preview your files in a single clean, uncluttered interface. Smart storage. With simple drag-and-drop functionality,... Read more
Cyberduck 4.5 - FTP and SFTP browser. (F...
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

Latest Forum Discussions

See All

LEX Goes Free For One Day In Honor of Ne...
LEX Goes Free For One Day In Honor of New Update Posted by Jennifer Allen on July 24th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Thomas Was Alone Goes Universal, Slashes...
Thomas Was Alone Goes Universal, Slashes Price to $3.99 Posted by Ellis Spice on July 24th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Meerkatz Challenge Review
Meerkatz Challenge Review By Jennifer Allen on July 24th, 2014 Our Rating: :: FONDLY PUZZLINGUniversal App - Designed for iPhone and iPad Cute and challenging, Meerkatz Challenge is a fun puzzle game, particularly for fans of... | Read more »
Book Your Appointment with F.E.A.R. this...
Book Your Appointment with F.E.A.R. | Read more »
It Came From Canada: Epic Skater
For all the hate that it gets for being a pastime for slackers, skateboarding really does require a lot of skill. All those flips and spins take real athleticism, and there’s all the jargon to memorize. Fortunately for us less extreme individuals,... | Read more »
Cultures Review
Cultures Review By Jennifer Allen on July 24th, 2014 Our Rating: :: SLOW-PACED EMPIRE BUILDINGiPad Only App - Designed for the iPad Cute it might seem, but Cultures is a bit too slow paced when it comes to those pesky timers to... | Read more »
More Paintings Have Been Added to Paint...
More Paintings Have Been Added to Paint it Back! Posted by Jessica Fisher on July 24th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
The Order of Souls Review
The Order of Souls Review By Campbell Bird on July 24th, 2014 Our Rating: :: STORY GRINDUniversal App - Designed for iPhone and iPad The Order of Souls is a free-to-play, turn-based RPG with a genre-mixing art style, interesting... | Read more »
Revolution 60 Review
Revolution 60 Review By Jordan Minor on July 24th, 2014 Our Rating: :: LASS EFFECTUniversal App - Designed for iPhone and iPad Revolution 60 is a bold, cinematic action game with ambition to spare.   | Read more »
Matter (Photography)
Matter 1.0.1 Device: iOS Universal Category: Photography Price: $1.99, Version: 1.0.1 (iTunes) Description: Add stunning 3D effects to your photos with real-time shadows and reflections. Export your creations as photos or video loops... | Read more »

Price Scanner via MacPrices.net

What Should Apple’s Next MacBook Priority Be;...
Stabley Times’ Phil Moore says that after expanding its iMac lineup with a new low end model, Apple’s next Mac hardware decision will be how it wants to approach expanding its MacBook lineup as well... Read more
ArtRage For iPhone Painting App Free During C...
ArtRage for iPhone is currently being offered for free (regularly $1.99) during Comic-Con San Diego #SDCC, July 24-27, in celebration of the upcoming ArtRage 4.5 and other 64-bit versions of the... Read more
With The Apple/IBM Alliance, Is The iPad Now...
Almost since the iPad was rolled out in 2010, and especially after Apple made a 128 GB storage configuration available in 2012, there’s been debate over whether the iPad is a serious tool for... Read more
MacBook Airs on sale starting at $799, free s...
B&H Photo has the new 2014 MacBook Airs on sale for up to $100 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels... Read more
Apple 27″ Thunderbolt Display (refurbished) a...
The Apple Store has Apple Certified Refurbished 27″ Thunderbolt Displays available for $799 including free shipping. That’s $200 off the cost of new models. Read more
WaterField Designs Unveils Cycling Ride Pouch...
High end computer case and bag maker WaterField Designs of San Francisco now enters the cycling market with the introduction of the Cycling Ride Pouch – an upscale toolkit with a scratch-free iPhone... Read more
Kingston Digital Ships Large Capacity Near 1T...
Kingston Digital, Inc., the Flash memory affiliate of Kingston Technology Company, Inc.,has announced its latest addition to the SSDNow V300 series, the V310. The Kingston SSDNow V310 solid-state... Read more
Apple’s Fiscal Third Quarter Results; Record...
Apple has announced financial results for its fiscal 2014 third quarter ended June 28, 2014, racking up quarterly revenue of $37.4 billion and quarterly net profit of $7.7 billion, or $1.28 per... Read more
15-inch 2.0GHz MacBook Pro Retina on sale for...
B&H Photo has the 15″ 2.0GHz Retina MacBook Pro on sale for $1829 including free shipping plus NY sales tax only. Their price is $170 off MSRP. B&H will also include free copies of Parallels... Read more
Apple restocks refurbished Mac minis for up t...
The Apple Store has restocked Apple Certified Refurbished Mac minis for up to $150 off the cost of new models. Apple’s one-year warranty is included with each mini, and shipping is free: - 2.5GHz Mac... Read more

Jobs Board

Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
Senior Interaction Designer, *Apple* Online...
**Job Summary** Apple is looking for a hands on Senior…will be a key player in designing for the Apple Online Store. The ideal designer will have a Read more
*Apple* Sales Chat Rep - Apple (United State...
…is looking for motivated, outgoing, and tech savvy individuals who want to offer Apple Customers an unparalleled customer experience over chat. At Apple , we believe Read more
Mac Expert - *Apple* Online Store Mexico -...
…MUST be fluent in English and Spanish to be considered for this position At Apple , we believe that hard work, a fun environment, creativity and innovation fuel the Read more
*Apple* Industrial Design CAD Sculptor - App...
**Job Summary** The Apple Industrial Design team is looking for a CAD sculptor/Digital 3D modeler to create high quality CAD models used in the industrial design process Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.