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

iFFmpeg 6.4.3 - Convert multimedia files...
iFFmpeg is a comprehensive media tool to convert movie, audio and media files between formats. The FFmpeg command line instructions can be very hard to master/understand, so iFFmpeg does all the hard... Read more
Alfred 3.4.1 - Quick launcher for apps a...
Alfred is an award-winning productivity application for OS X. Alfred saves you time when you search for files online or on your Mac. Be more productive with hotkeys, keywords, and file actions at... Read more
SyncTwoFolders 2.2.4 - Syncs two user-sp...
SyncTwoFolders simply synchronizes two folders. It supports synchronization across mounted network drives and it is a possibility to run a simulation showing in a log what will be done. Please visit... Read more
Maintenance 2.2.7 - System maintenance u...
Maintenance is a system maintenance and cleaning utility. It allows you to run miscellaneous tasks of system maintenance: Check the status of the hard disk Repair permissions Run periodic scripts... Read more
Hopper Disassembler 4.2.13- - Binary dis...
Hopper Disassembler is a binary disassembler, decompiler, and debugger for 32- and 64-bit executables. It will let you disassemble any binary you want, and provide you all the information about its... Read more
NeoOffice 2017 - Mac-tailored, OpenOffic...
NeoOffice is a complete office suite for OS X. With NeoOffice, users can view, edit, and save OpenOffice documents, PDF files, and most Microsoft Word, Excel, and PowerPoint documents. NeoOffice 3.x... Read more
Firefox 55.0.2 - 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
Alfred 3.4.1 - Quick launcher for apps a...
Alfred is an award-winning productivity application for OS X. Alfred saves you time when you search for files online or on your Mac. Be more productive with hotkeys, keywords, and file actions at... Read more
Maintenance 2.2.7 - System maintenance u...
Maintenance is a system maintenance and cleaning utility. It allows you to run miscellaneous tasks of system maintenance: Check the status of the hard disk Repair permissions Run periodic scripts... Read more
NeoOffice 2017 - Mac-tailored, OpenOffic...
NeoOffice is a complete office suite for OS X. With NeoOffice, users can view, edit, and save OpenOffice documents, PDF files, and most Microsoft Word, Excel, and PowerPoint documents. NeoOffice 3.x... Read more

War Wings beginner's guide - how to...
War Wings is the newest project from well-established game maker Miniclip. It's a World War II aerial dogfighting game with loads of different airplane models to unlock and battle. The game offers plenty of single player and multiplayer action. We... | Read more »
How to win every 2v2 battle in Clash Roy...
2v2 is coming back to Clash Royale in a big way. Although it's only been available for temporary periods of time, 2v2 has seen a hugely positive fan response, with players clamoring for more team-based gameplay. Soon we'll get yet another taste of... | Read more »
Roll to Win with Game of Dice’s new upda...
Joycity’s hit Game of Dice gets a big new update this week, introducing new maps, mechanics, and even costumes. The update sets players loose on an exciting new map, The Cursed Tower, that allows folks to use special Runes mid-match. If you feel... | Read more »
Bottom of the 9th (Games)
Bottom of the 9th 1.0.1 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.0.1 (iTunes) Description: Play the most exciting moment of baseball in this fast-paced dice and card game! | Read more »
The best apps for viewing the solar ecli...
If you somehow missed the news, many parts of the United States will be witness to a total solar eclipse on August 21 for the first time in over 90 years. It'll be possible to see the eclipse in at least some capacity throughout the continental U... | Read more »
The 5 best mobile survival games
Games like ARK: Survival Evolved and Conan Exiles have taken the world of gaming by storm. The market is now flooded with hardcore survival games that send players off into the game's world with nothing but maybe the clothes on their back. Never... | Read more »
Portal Walk (Games)
Portal Walk 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Portal Walk is adventure and relaxing platform game about Eugene. Eugene stuck between worlds and trying to find way back home.... | Read more »
Technobabylon (Games)
Technobabylon 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: City of Newton, 2087. Genetic engineering is the norm, the addictive Trance has replaced almost any need for human interaction,... | Read more »
5 reasons why 2v2 is the best mode in Cl...
Supercell has been teasing fans with 2v2 windows that allow players to team up for limited periods of time. The Summer of 2v2 was just this past July, but players are already clamoring for more of that sweet, sweet team-based action. The fans have... | Read more »
The best deals on the App Store this wee...
It seems like the week's only just started, and yet here we are with a huge pile of discounted games to sort through. There are some real doozies on sale this week. We're talking some truly stellar titles. Let's take a look at four of the best... | Read more »

Price Scanner via MacPrices.net

13-inch 2.3GHz MacBook Pros on sale for $100...
Amazon has the new 2017 13″ 2.3GHz MacBook Pros on sale today for $100 off MSRP, each including free shipping: – 13″ 2.3GHz/128GB Space Gray MacBook Pro (MPXQ2LL/A): $1199.99 $100 off MSRP – 13″ 2.... Read more
New iOS 11 Productivity Features Welcome But...
The iOS community is in late summer holding mode awaiting the September arrival of the iPhone 8 and iOS 11. iOS 11 public betas have been available for months — number six was released this week —... Read more
Samsung Electronics Launches New Portable SSD...
Samsung Electronics America, Inc. has announced the launch of Samsung Portable SSD T5 – its newest portable solid state drive (PSSD) that raises the bar for the performance of external memory... Read more
TrendForce Reports YoY Gain of 3.6% for 2Q17...
Market research firm TrendForce reports that the global notebook shipments for this second quarter registered a sequential quarterly increase of 5.7% and a year-on-year increase of 3.6%, totaling 39.... Read more
Sale! 10-inch iPad Pros for $50 off MSRP, no...
B&H Photo has 10.5″ iPad Pros in stock today and on sale for $50 off MSRP. Each iPad includes free shipping, and B&H charges sales tax in NY & NJ only: – 10.5″ 64GB iPad Pro: $599, save $... Read more
Sale! 2017 13-inch Silver 2.3GHz MacBook Pro...
Amazon has new 2017 13″ 2.3GHz/128GB Silver MacBook Pro on sale today for $100 off MSRP including free shipping. Their price is the lowest available for this model from any reseller: – 13″ 2.3GHz/... Read more
WaterField Unveils Collaboratively-Designed,...
In collaboration with customers and seasoned travelers, San Francisco maker WaterField Designs set out to create the preeminent carry-on system to improve the experience of frequent fliers. The... Read more
Miya Notes Mac-Client for Google Keep (Launch...
MacPlus Software has announced te launch of Miya Notes for Google Keep 1.0, a powerful Mac-client for Google Keep. Millions of people use Google Keep on their phones and online, but a convenient Mac... Read more
Apple refurbished iMacs available starting at...
Apple has previous-generation Certified Refurbished 2015 21″ & 27″ iMacs available starting at $849. Apple’s one-year warranty is standard, and shipping is free. The following models are... Read more
2017 13-inch MacBook Airs on sale for $100 of...
B&H Photo new 2017 13″ MacBook Airs on sale today for $100 off MSRP, starting at $899: – 13″ 1.8GHz/128GB MacBook Air (MQD32LL/A): $899, $100 off MSRP – 13″ 1.8GHz/256GB MacBook Air (MQD42LL/A... Read more

Jobs Board

Business Development Manager - *Apple* Medi...
Job Summary Apple Music is a single, intuitive app that...- all in one place. You can stream any Apple Music song, playlist or album, and download it Read more
Development Operations and Site Reliability E...
Development Operations and Site Reliability Engineer, Apple Payment Gateway Job Number: 57572631 Santa Clara Valley, California, United States Posted: Jul. 27, 2017 Read more
Frameworks Engineering Manager, *Apple* Wat...
Frameworks Engineering Manager, Apple Watch Job Number: 41632321 Santa Clara Valley, California, United States Posted: Jun. 15, 2017 Weekly Hours: 40.00 Job Summary Read more
Program Manager, *Apple* Pay Business Opera...
…Manager to deliver and sustain a seamless user and support experience for Apple Pay Cash, the upcoming person-to-person payments feature in iMessage. On the Business Read more
Sr. Software Engineer, Core Services, *Apple...
…You will be part of the server team that powers various features within the Apple client applications - iTunes, App Store, iBooks, Podcast, Apple Music etc. You Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.