TweetFollow Us on Twitter

Mar 96 Challenge
Volume Number:12
Issue Number:3
Column Tag:Programmer’s Challenge

Programmer’s Challenge

By Bob Boonstra, Westford, Massachusetts

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

Words The Reverse

Text input, of Block given a in words of order the place (in reverse) will that routine a write to is challenge the month this. Oops, what I meant to say was: This month, the Challenge is to write a routine that will reverse (in place) the order of words in a given block of input text. The prototype for the code you should write is:

pascal void ReverseTheWords(
 const char *text, /* the words you should reverse */
 const long numCharsIn    /* length of inputText in chars */
);

Specifically, ReverseTheWords should exchange the first word in the input text with the last word, the second word with the next-to-last word, etc. For the purpose of this Challenge, a word is defined as a continuous sequence of alphanumeric characters [a..zA..Z0..9]. Any nonalphanumeric characters should remain in their original positions and in their original order with respect to the new words; that is, punctuation, white space, and other characters between the first and second input words should, on output, be located between the new first and second words. As an example, ReverseTheWords would convert:

 This, however, <-is-> a (difficult) test.

into

 Test, difficult, <-a-> is (however) this.

As you can see from the example, there is one additional requirement. Your code needs to adjust the capitalization of words so that the n-th word is capitalized on output only if the n-th word was capitalized in the input text.

There are no specific restrictions on the amount of auxiliary memory you may use (within reason), so you may allocate a few buffers of size numCharsIn should you need them. Remember, however, to deallocate any memory you allocate before returning, as I will be calling your code many times.

Note that the prototype specifies the use of Pascal calling conventions. That is because this month we are conducting

A Language Experiment

Over the past months, in response to suggestions from readers, we have made a number of changes to the Challenge, including migrating to PowerPC native code and expanding to other C compilers. Now we are experimenting with some additional changes. This month, for the first time, your solution to the Challenge can be coded in C, C++, or Pascal, using your choice among the MPW, Metrowerks, or Symantec compilers for these languages. Although either 68K or PowerPC code is permitted, I will be running your code on a PowerMac 8500, so native code is obviously recommended. The environment you choose must support linking your solution with test code written in C. Along with your solution, you should specify the intended environment, compiler and compiler options, or (better yet) provide a project file or make file that will generate a stand-alone application that calls your solution from C test code.

Two Months Ago Winner

Congratulations to Jorg “jbx” Brown and Eric Gundrum for submitting the fastest entry to the Sliding Tiles Challenge. Contestants were asked to unscramble an N¥M grid of interlocking tiles, where a tile could be moved horizontally or vertically into the empty tile location. Fourteen of the 16 entries submitted worked correctly. The table below presents selected results from the timing tests, which used puzzles ranging in size from 8¥8 to 100¥300. (Two of the entries worked too slowly to complete the entire test suite.)

The most common solution technique involved solving the puzzle row-by-row from the bottom, being careful not to disturb tiles that had already been moved into their correct positions. The top two rows were solved together, starting from the right column and working left. Several solutions, including the winners’ and the even more move-efficient second-place entry by Peter Lewis, refined this by using a “greedy” algorithm that solves the bottom row and right column first, then moves to the next row and column. Since the problem involved use of a given callback routine for each move, it was important to reduce the number of tile moves. Some solutions moved tiles primarily in horizontal and vertical directions; others (including the winners’) devised operators that moved a tile diagonally in fewer moves.

Thanks to Greg Linden for sending me a reference to an article on this subject in Information Processing Letters (Oct. 1995). In that article, Ian Parberry (University of North Texas) establishes some bounds on algorithms for the n2-1 puzzle (the square version of this Challenge). The article proves that the “greedy” algorithm requires at most 5n3 moves in the worst case, and that any algorithm must make at least n3 moves (ignoring lower-order terms for both bounds). While a better algorithm may exist, Ian speculates that the lower bound could be made tighter. Interested readers can contact the author at ian@cs.unt.edu, or browse his web page at http://hercule.csci.unt.edu/ian.

Here are the times for each of the correct entries. Numbers in parentheses after a person’s name indicate that person’s cumulative point total for all previous Challenges, not including this one.

Time Time Total # of Moves

Name 20x20 100x300 Time (Millions)

Jorg Brown (10)

& Eric Gundrum 183 175730 261694 249

Peter Lewis 195 197905 294931 228

Christopher Phillips 211 200368 302774 269

Ludovic Nicolle 252 220952 337386 300

Ernst Munter (110) 159 258165 365894 295

Randy Boring 386 309630 481609 307

Cathy Saxton 264 338127 496610 299

Rishi Khan (age 16) 284 350763 506952 320

Xan Gregg (88) 296 360735 531493 299

Tom Saxton (10) 333 404155 592967 339

Miguel Cruz Picão(7) 245 652588 912267 339

John Sweeney (4) 300 875362 1223956 321

A. K. * * * *

G. L. * * * *

Top Contestants Of All Time

Here are the Top Contestants for the Programmer’s Challenges to date, including everyone who has accumulated more than 20 points. The numbers below include points awarded for this month’s entrants.

Rank Name Points Rank Name Points

1. [Name deleted] 176 11. Mallett, Jeff 44

2. Munter, Ernst 112 12. Kasparian, Raffi 42

3. Gregg, Xan 88 13. Vineyard, Jeremy 42

4. Larsson, Gustav 87 14. Lengyel, Eric 40

5. Karsh, Bill 80 15. Darrah, Dave 31

6. Stenger, Allen 65 16. Brown, Jorg 30

7. Riha, Stepan 51 17. Landry, Larry 29

8. Cutts, Kevin 50 18. Elwertowski, Tom 24

9. Goebel, James 49 19. Lee, Johnny 22

10. Nepsund, Ronald 47 20. Noll, Robert 22

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 5th place 2 points

2nd place 10 points finding bug 2 points

3rd place 7 points suggesting Challenge 2 points

4th place 4 points

Here the winning solution by Jorg and Eric:

SlidingTiles.c

Written by Jorg Brown & Eric Gundrum

Thanks also to Brad Kollmyer

typedef Boolean (*MoveProc)(
  long tileToMoveRow, long tileToMoveCol);

static MoveProc gMakeMove;
static long *gTiles, gNumCols, *gPieceRow, *gPieceCol;
static long *gBlankSquare; // initialized by SolveTiles, updated by BlankXXX()

#define gBlankRow pieceRow[0]
#define gBlankCol pieceCol[0]

BlankUp
static void BlankUp() { // move the BLANK SQUARE up
   long   tile, *oldBlankSquare, *newBlankSquare;
   long   *pieceRow = gPieceRow;
   long   *pieceCol = gPieceCol;

   oldBlankSquare = gBlankSquare;
   gBlankSquare = newBlankSquare = oldBlankSquare - gNumCols;
   tile = *newBlankSquare;
   pieceRow[tile] = gBlankRow--;
   gMakeMove(gBlankRow, gBlankCol);
   *oldBlankSquare = tile;
   *newBlankSquare = 0;
}

BlankDown
static void BlankDown() { // move the BLANK SQUARE down
   long   tile, *oldBlankSquare, *newBlankSquare;
   long   *pieceRow = gPieceRow;
   long   *pieceCol = gPieceCol;

   oldBlankSquare = gBlankSquare;
   gBlankSquare = newBlankSquare = oldBlankSquare + gNumCols;
   tile = *newBlankSquare;
   pieceRow[tile] = gBlankRow++;
   gMakeMove(gBlankRow, gBlankCol);
   *oldBlankSquare = tile;
   *newBlankSquare = 0;
}

MoveBlankToRow
static void MoveBlankToRow(long destRow) {
   long   tile, *oldBlankSquare, *newBlankSquare;
   long   *pieceRow = gPieceRow;
   long   *pieceCol = gPieceCol;
   long   blankRow = gBlankRow;
   long   rowInc, BlankSquareInc;

   if (blankRow < destRow) { // move DOWN
      rowInc = 1;
      BlankSquareInc = gNumCols;
   } else if (blankRow > destRow) { // move UP
      rowInc = -1;
      BlankSquareInc = -gNumCols;
   } else return;

   oldBlankSquare = gBlankSquare;
   do {
      newBlankSquare = oldBlankSquare + BlankSquareInc;
      tile = *newBlankSquare;
      pieceRow[tile] = blankRow;
      blankRow += rowInc;
      gMakeMove(blankRow, gBlankCol);
      *oldBlankSquare = tile;
      *newBlankSquare = 0;
      oldBlankSquare = newBlankSquare;
   } while (blankRow != destRow);
   gBlankSquare = newBlankSquare;
   gBlankRow = blankRow;
}

BlankLeft
static void BlankLeft() { // move the BLANK SQUARE left
   long   tile, *oldBlankSquare, *newBlankSquare;
   long   *pieceRow = gPieceRow;
   long   *pieceCol = gPieceCol;

   oldBlankSquare = gBlankSquare;
   gBlankSquare = newBlankSquare = oldBlankSquare - 1;
   tile = *newBlankSquare;
   pieceCol[tile] = gBlankCol--;
   gMakeMove(gBlankRow, gBlankCol);
   *oldBlankSquare = tile;
   *newBlankSquare = 0;
}


BlankRight
static void BlankRight() { // move the BLANK SQUARE right
   long   tile, *oldBlankSquare, *newBlankSquare;
   long   *pieceRow = gPieceRow;
   long   *pieceCol = gPieceCol;

   oldBlankSquare = gBlankSquare;
   gBlankSquare = newBlankSquare = oldBlankSquare + 1;
   tile = *newBlankSquare;
   pieceCol[tile] = gBlankCol++;
   gMakeMove(gBlankRow, gBlankCol);
   *oldBlankSquare = tile;
   *newBlankSquare = 0;
}

MoveBlankToCol
static void MoveBlankToCol(long destCol) {
   long   tile, *oldBlankSquare, *newBlankSquare;
   long   *pieceRow = gPieceRow;
   long   *pieceCol = gPieceCol;
   long   blankCol = gBlankCol;
   long   inc;

   if (blankCol < destCol) { // move RIGHT
      inc = 1;
   } else if (blankCol > destCol) { // move LEFT
      inc = -1;
   } else return;

   oldBlankSquare = gBlankSquare;
   do {
      newBlankSquare = oldBlankSquare + inc;
      tile = *newBlankSquare;
      pieceCol[tile] = blankCol;
      blankCol += inc;
      gMakeMove(gBlankRow, blankCol);
      *oldBlankSquare = tile;
      *newBlankSquare = 0;
      oldBlankSquare = newBlankSquare;
   } while (blankCol != destCol);
   gBlankSquare = newBlankSquare;
   gBlankCol = blankCol;
}

MoveAPiece

static void MoveAPiece(long piece, long destRow, long destCol, 
 long nextPiece) {
   long   sourceRow, sourceCol;
   long   *pieceRow = gPieceRow;
   long   *pieceCol = gPieceCol;
   long   nextRow = gNumCols;

   sourceRow = pieceRow[piece];
   sourceCol = pieceCol[piece];

   if (sourceRow >= destRow) { 
      // in this case, we have to move the tile up (or directly right) to get to its destination
      if (sourceRow == destRow) {
         if (sourceCol == destCol) return;

         // simplify: move the blank so that it is not to the right of the target
         if (gBlankCol > destCol) {
            MoveBlankToCol(destCol);
         }

         // move the blank to the left of the source, possibly moving the source
         // to the right at the same time.
         if (gBlankRow != destRow) {
            if (sourceCol == destCol-1 && gBlankRow > destRow) {
               MoveBlankToCol(sourceCol - 1);
               MoveBlankToRow(sourceRow - 1);
               BlankRight(); BlankRight();
               BlankDown();  BlankLeft();
               return; // all done
            } else {
               MoveBlankToCol(sourceCol + 1);
               MoveBlankToRow(sourceRow);
               BlankLeft();
               sourceCol++;
            }
         } else {
            if (gBlankCol < sourceCol) {
               MoveBlankToCol(sourceCol - 1);
            } else {
               MoveBlankToCol(sourceCol);
               sourceCol++;
            }
         }
         
WereOnTheSameRowNow:
         // at this point, the blank is to the left of the source,
         // and the puzzle might very well be done already.
         while (sourceCol != destCol) {
            if (nextPiece == piece - 1) { // into a row?
               if (gBlankCol != 0 && 
                     pieceCol[nextPiece]-pieceRow[nextPiece] <= 
                     gBlankCol-gBlankRow) {
                  MoveAPiece(nextPiece, gBlankRow, gBlankCol, 
                               nextPiece - 1);
               }
               if (gBlankRow == destRow) 
                 while ((gBlankSquare[-1] == gBlankSquare[1] - 1) 
                        && gBlankCol != 0) {
                  BlankLeft();
               }
            }
            if (gBlankRow == destRow) BlankUp();
            do {
               BlankRight();
            } while (gBlankCol <= sourceCol);
            BlankDown();  BlankLeft();  sourceCol++;
         }
         return;
      }
      // simplify: move the blank so that it is to the left of the target
      if (gBlankCol >= destCol) {
         MoveBlankToCol(destCol - 1);
      }
      // simplify: move the blank so that it is not above the target.
      if (gBlankRow < destRow) MoveBlankToRow(destRow);

again1:   // simplify: if the blank is below the source, move it so it’s not.
      sourceRow = pieceRow[piece];
      sourceCol = pieceCol[piece];
      if (gBlankRow >= sourceRow) {
         // if the blank is in the same column, move it away first.
         if (gBlankCol == sourceCol) {
            if (gBlankCol == destCol - 1) {
               BlankLeft();
            } else {
               BlankRight();
            }
         }
         // now that they're in different columns, move the blank so it’s not below
         MoveBlankToRow(sourceRow);
      }
      // simplify: if the blank is on the same row, and to the left, move up.
      if (gBlankRow == sourceRow && gBlankCol < sourceCol) {
         BlankUp();
      }
      // simplify: if the blank is to the left, move it to the same column.
      if (gBlankCol < sourceCol) {
         MoveBlankToCol(sourceCol);
      }
      // simplify: if the blank is to the upper right, move it to the left and down.
      if (gBlankRow < sourceRow) {
         if (gBlankCol > sourceCol) {
            MoveBlankToCol(sourceCol);
         }
         if (gBlankRow < sourceRow - 1) {
            MoveBlankToRow(sourceRow - 1);
         }
      }
      // if the blank is off to the right, move it next to the source.
      while (gBlankCol > sourceCol + 1) {
         MoveBlankToCol(sourceCol + 1);
      }
      // at this point, the blank should be either just above or just right of the piece.
      if (gBlankCol == sourceCol) {
         if (gBlankRow != sourceRow - 1) Debugger();
      } else {
         if (gBlankRow != sourceRow) Debugger();
         if (gBlankCol != sourceCol + 1) Debugger();
         BlankLeft();  BlankUp();    BlankRight();
      }
      BlankDown();
      sourceRow = pieceRow[piece];
      sourceCol = pieceCol[piece];
      if (sourceRow != destRow) goto again1;
      if (gBlankCol != destCol - 1) {
         BlankRight(); BlankUp();    BlankLeft();
         while (pieceCol[piece] != destCol) {
            BlankUp();    BlankRight(); BlankRight();
            BlankDown();  BlankLeft();
         }
         return; // DONE!!!!
      }
      BlankLeft();  BlankUp();    BlankUp();    BlankRight(); 
      BlankRight(); BlankDown();  BlankLeft();
      return; // DONE!!!!
   }

   // at this point, we know that source is above our destination.
   if (sourceCol >= destCol) { 
      // in this case, we have to move the tile left (or directly down) to get to its destination
      if (sourceCol == destCol) {

         // simplify: move the blank so that it is not below the target
         if (gBlankRow > destRow) {
            MoveBlankToRow(destRow);
         }

         // move the blank above the source, possibly moving the source
         // down at the same time.
         if (gBlankCol != destCol) {
            if (sourceRow == destRow-1 && gBlankCol > destCol) {
               MoveBlankToRow(sourceRow - 1);
               MoveBlankToCol(sourceCol - 1);
               BlankDown();  BlankDown();
               BlankRight(); BlankUp();
               return; // all done
            } else {
               MoveBlankToRow(sourceRow + 1);
               MoveBlankToCol(sourceCol);
               BlankUp();
               sourceRow++;
            }
         } else {
            if (gBlankRow < sourceRow) {
               MoveBlankToRow(sourceRow - 1);
            } else {
               MoveBlankToRow(sourceRow);
               sourceRow++;
            }
         }
         
WereInTheSameColumnNow:
         // at this point, the blank is on top of the source,
         // and the puzzle might very well be done already.
         while (sourceRow != destRow) {
            if (nextPiece == piece - nextRow) { // into a column?
               if (gBlankRow != 0 && 
                   pieceCol[nextPiece]-pieceRow[nextPiece] >= 
                     gBlankCol-gBlankRow) {
                  MoveAPiece(nextPiece, gBlankRow, gBlankCol, 
                               nextPiece - nextRow);
               }
               if (gBlankCol == destCol) 
                 while ((gBlankSquare[-nextRow] == 
                         gBlankSquare[nextRow] - 1) && 
                        gBlankRow != 0) {
                  BlankUp();
               }
            }
            if (gBlankCol == destCol) BlankLeft();
            do {
               BlankDown();
            } while (gBlankRow <= sourceRow);
            BlankRight(); BlankUp();    sourceRow++;
         }
         return;
      }
      // simplify: move the blank so that it is to the up of the target
      if (gBlankRow >= destRow) {
         MoveBlankToRow(destRow - 1);
      }
      // simplify: move the blank so that it is not to the left of the target.
      if (gBlankCol < destCol) MoveBlankToCol(destCol);

again2:   // simplify: if the blank is to the right of the source, move it so it’s not.
      sourceRow = pieceRow[piece];
      sourceCol = pieceCol[piece];
      if (gBlankCol >= sourceCol) {
         // if the blank is in the same row, move it away first.
         if (gBlankRow == sourceRow) {
            if (gBlankRow == destRow - 1) {
               BlankUp();
            } else {
               BlankDown();
            }
         }
         // now that they’re in different rows, move the blank so it’s not to the right of
         MoveBlankToCol(sourceCol);
      }
      // simplify: if the blank is on the same column, and to the up, move left.
      if (gBlankCol == sourceCol && gBlankRow < sourceRow) {
         BlankLeft();
      }
      // simplify: if the blank is to the up, move it to the same row.
      if (gBlankRow < sourceRow) {
         MoveBlankToRow(sourceRow);
      }
      // simplify: if the blank is to the lower left, move it to the right and up.
      if (gBlankCol < sourceCol) {
         if (gBlankRow > sourceRow) {
            MoveBlankToRow(sourceRow);
         }
         if (gBlankCol < sourceCol - 1) {
            MoveBlankToCol(sourceCol - 1);
         }
      }
      // if the blank is off to the down, move it next to the source.
      while (gBlankRow > sourceRow + 1) {
         MoveBlankToRow(sourceRow + 1);
      }
      // at this point, the blank should be either just below or just to the left of the piece.
      if (gBlankRow == sourceRow) {
         if (gBlankCol != sourceCol - 1) Debugger();
      } else {
         if (gBlankCol != sourceCol) Debugger();
         if (gBlankRow != sourceRow + 1) Debugger();
         BlankUp();    BlankLeft();  BlankDown();
      }
      BlankRight();
      sourceRow = pieceRow[piece];
      sourceCol = pieceCol[piece];
      if (sourceCol != destCol) goto again2;
      if (gBlankRow != destRow - 1) {
         BlankDown();  BlankLeft();  BlankUp();
         while (pieceRow[piece] != destRow) {
            BlankLeft();  BlankDown();
            BlankDown();  BlankRight(); BlankUp();
         }
         return; // DONE!!!!
      }
      BlankUp();    BlankLeft();  BlankLeft();  BlankDown();
      BlankDown();  BlankRight(); BlankUp();
      return; // DONE!!!!
   }

   // at this point, we know that we are above and to the left of our destination.

   if (destCol - sourceCol == destRow - sourceRow) {
      // we’re on the diagonal.
      if (gBlankCol >= sourceCol) {
         if (gBlankRow <= sourceRow) goto MoveSrcRightFirst;
      }
      if (gBlankRow >= sourceRow) {
         if (gBlankCol <= sourceCol) goto MoveSrcDownFirst;
      }
      if (gPieceRow[nextPiece] - gPieceCol[nextPiece] > 
          destRow - destCol) {
         // relative to the destination, the next piece is to the lower left.
         // this means we want the blank to end up to the left of the target,
         // rather than above it.
         goto MoveSrcDownFirst;
      }
      goto MoveSrcRightFirst;
   }
   if (destCol - sourceCol < destRow - sourceRow) {
MoveSrcDownFirst:
      // the source is within the 90š-135š octant.
      // we want to move the blank square just below the source.
      // we will end up just to the left of the target.
      if (gBlankCol == sourceCol && gBlankRow < sourceRow) {
         // the blank is on top of the source.  moving it
         // down would move our square in the wrong direction.
         BlankRight();
      }
      // in case the source is just to the upper left of the target,
      // we have to make sure we don’t accidentally munge the protected area.
      if (gBlankCol > destCol) MoveBlankToCol(destCol);
      MoveBlankToRow(sourceRow + 1);
      MoveBlankToCol(sourceCol);
      BlankUp();    sourceRow++;
      BlankRight(); BlankDown();
      // the blank is now to the right of the source.
   } else {
MoveSrcRightFirst:
      // the source is within the 135š-180š octant.
      // we want to move the blank square just to the right of the source.
      // we will end up just above the target.
      if (gBlankRow == sourceRow && gBlankCol < sourceCol) {
         // the blank is to the left of the source.  moving it
         // to the right would move our square in the wrong direction.
         BlankDown();
      }
      // in case the source is just to the upper left of the target,
      // we have to make sure we don't accidentally munge the protected area.
      if (gBlankRow > destRow) MoveBlankToRow(destRow);
      MoveBlankToCol(sourceCol + 1);
      MoveBlankToRow(sourceRow);
      // the blank is now to the right of the source.
   }
   BlankLeft();
   sourceCol++;
   // the blank is now to the left of the source.
   // are we done yet?
   for (;;) {
      if (sourceCol == destCol) {
         if (sourceRow == destRow) return;
         // the blank is still to the left of the source.
         BlankDown();  BlankRight(); BlankUp();   sourceRow++;
         goto WereInTheSameColumnNow;
      }
      if (sourceRow == destRow) {
         goto WereOnTheSameRowNow;
      }
      BlankDown();  BlankRight(); BlankUp();    sourceRow++;
      BlankRight(); BlankDown();  BlankLeft();  sourceCol++;
   }
}

QuickBlock
static void *QuickBlock(long size) {
   Handle   h = NewHandle(size);
   if (h == 0) return 0;
   HLock(h);
   return *h;
}

DisposeBlock
static void DisposeBlock(void *block) {
   Handle   h = RecoverHandle(block);
   DisposeHandle(h);
}


SolveTiles
void SolveTiles(
  long *tiles,      /* pointer to array of tiles where */
  long numRows,     /*   tile (row,col) is at */
  long numCols,     /*   *(tiles + row*numCols + col) */
  MoveProc MakeMove /* Callback procedure to move a tile */
) {
   long   col, row, target, tile, correctTile;
   long   colsToGo, rowsToGo;
   long   *tileRover, *pieceRow, *pieceCol;

   pieceRow = QuickBlock(numRows * numCols * sizeof(long));
   if (pieceRow == 0) return;
   pieceCol = QuickBlock(numRows * numCols * sizeof(long));
   if (pieceCol == 0) {
      DisposeBlock(pieceRow);
      return;
   }
   gPieceRow = pieceRow;
   gPieceCol = pieceCol;
   gMakeMove = MakeMove;
   gTiles = tiles;
   gNumCols = numCols;

   tileRover = tiles;
   correctTile = 0;
   for (row = 0; row < numRows; row++) {
      for (col = 0; col < numCols; col++) {
         tile = *tileRover++;
         pieceRow[tile] = row;
         pieceCol[tile] = col;
         correctTile++;
      }
   }

   gBlankSquare = &tiles[gBlankRow * numCols + gBlankCol];

   rowsToGo = numRows;
   colsToGo = numCols;

   for (;;) {
      if (rowsToGo >= colsToGo) {
         if (rowsToGo <= 2) break;
         row = rowsToGo - 1;
         for (col = colsToGo - 1; col > 1; col--) {
            tile = row * numCols + col;
            MoveAPiece(tile, row, col, tile - 1);
         }
         tile = row * numCols;
         if (pieceRow[tile]     != row || 
             pieceCol[tile    ] != 0   ||
             pieceRow[tile + 1] != row || 
             pieceCol[tile + 1] != 1) {
            MoveAPiece(tile, row, 1, tile + 1);
            if (gBlankRow == row) {
               if (tiles[(row - 1) * numCols] == tile + 1) {
                  // problem scenario 1
rowScenario1:
                  BlankRight(); BlankUp();    BlankLeft();
                  BlankUp();    BlankRight(); BlankDown();
                  BlankDown();  BlankLeft();  BlankUp();
                  BlankRight(); BlankUp();    BlankLeft();
                  BlankDown();  BlankDown();  BlankRight();
                  BlankUp();
                  goto nextRow;
               }
            } else if (tiles[row * numCols] == tile + 1) {
               // problem scenario 2
               MoveBlankToCol(0);
               MoveBlankToRow(row);
               goto rowScenario1;
            }
            MoveAPiece(tile + 1, row, 1, 0);
         }
nextRow:   if (gBlankRow == row) BlankUp();
         if (pieceRow[tile]     != row || 
             pieceCol[tile    ] != 0) {
            // the “12” isn’t in place...
            Debugger();
         }
      rowsToGo--;
      } else {
         if (colsToGo <= 2) break;
         col = colsToGo - 1;
         for (row = rowsToGo - 1; row > 1; row--) {
            tile = row * numCols + col;
            MoveAPiece(tile, row, col, tile - numCols);
         }
         if (pieceRow[          col] != 0 || 
             pieceCol[          col] != col ||
             pieceRow[numCols + col] != 1 || 
             pieceCol[numCols + col] != col) {
            MoveAPiece(col, 1, col, col + numCols);
            if (gBlankCol == col) {
               if (tiles[col - 1] == numCols + col) {
                  // problem scenario 1
colScenario1:
                  BlankDown();  BlankLeft();  BlankUp();
                  BlankLeft();  BlankDown();  BlankRight();
                  BlankRight(); BlankUp();    BlankLeft();
                  BlankDown();  BlankLeft();  BlankUp();
                  BlankRight(); BlankRight(); BlankDown();
                  BlankLeft();
                  goto nextCol;
               }
            } else if (tiles[col] == numCols + col) {
               // problem scenario 2
               MoveBlankToRow(0);
               MoveBlankToCol(col);
               goto colScenario1;
            }
            MoveAPiece(numCols + col, 1, col, 0);
         }
nextCol:   if (gBlankCol == col) BlankLeft();
         if (pieceRow[          col] != 0 || 
             pieceCol[          col] != col) {
            // the “3” isn’t in place...
            Debugger();
         }
         colsToGo--;
      }
   }

   if (gBlankRow == 0) {
      if (gBlankCol == 0) {
         if (pieceRow[1] == 0) goto pos0123;
         if (pieceCol[1] == 0) goto pos0312;
                               goto pos0231;
      } else {
         if (pieceRow[1] == 0) goto pos1023;
         if (pieceCol[1] == 0) goto pos3012;
                               goto pos2031;
      }
   } else {
      if (gBlankCol == 0) {
         if (pieceRow[1] != 0) goto pos3201;
         if (pieceCol[1] == 0) goto pos1302;
                               goto pos2103;
      } else {
         if (pieceRow[1] != 0) goto pos3210;
         if (pieceCol[1] == 0) goto pos1320;
                               goto pos2130;
      }
   }

pos3012: BlankLeft();
pos0312: BlankDown();
pos1302: BlankRight();
pos1320: BlankUp();
pos1023: BlankLeft();
         goto all_done;

pos3210: BlankLeft();
pos3201: BlankUp();
pos0231: BlankRight();
pos2031: BlankDown();
pos2130: BlankLeft();
pos2103: BlankUp();
pos0123: goto all_done;

all_done:
   DisposeBlock(pieceRow); gPieceRow = 0;
   DisposeBlock(pieceCol); gPieceCol = 0;
}

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Lyn 1.8.5 - Lightweight image browser an...
Lyn is a fast, lightweight image browser and viewer designed for photographers, graphic artists, and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it delivers... Read more
Apple iOS 10.2.1 - The latest version of...
iOS 10 is the biggest release of iOS ever. A massive update to Messages brings the power of the App Store to your conversations and makes messaging more personal than ever. Find your route with... Read more
Apple Security Update 2016-003 Supplemen...
Apple Security Update is recommended for all users and improves the security of OS X. For detailed information about the security content of this update, please visit: http://support.apple.com/kb/... Read more
Apple macOS Sierra 10.12.3 - The latest...
With Apple macOS Sierra, Siri makes its debut on Mac, with new features designed just for the desktop. Your Mac works with iCloud and your Apple devices in smart new ways, and intelligent... Read more
BetterTouchTool 1.992 - Customize Multi-...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom... Read more
Viber 6.5.5 - Send messages and make cal...
Viber lets you send free messages and make free calls to other Viber users, on any device and network, in any country! Viber syncs your contacts, messages and call history with your mobile device, so... Read more
Opera 42.0.2393.137 - High-performance W...
Opera is a fast and secure browser trusted by millions of users. With the intuitive interface, Speed Dial and visual bookmarks for organizing favorite sites, news feature with fresh, relevant content... Read more
iClock Pro 3.4.7 - Customize your menuba...
iClock Pro is a menu bar replacement clock for Apple's default clock. iClock Pro is an update, total rewrite and improvement to the popular iClock. Have the day, date and time in different fonts and... Read more
PhotoDesk 4.1.5 - Instagram client for p...
PhotoDesk lets you view, like, comment, and download Instagram pictures/videos. (NO Uploads! / Image Posting! Instagram forbids that! AND you need an existing Instagram account). But you can do so... Read more
Capo 3.5.1 - Slow down and learn to play...
Capo lets you slow down your favorite songs so you can hear the notes and learn how they are played. With Capo, you can quickly tab out your songs atop a highly-detailed OpenCL-powered spectrogram... Read more

Clash Royale gets some serious balance u...
| Read more »
Ironhide Game Studio prepares for a busy...
Kingdom Rush breathed fresh life into the tired tower defense genre way back in 2012. The game was a robust challenge that somehow managed to lift you up, rather than leaving you feeling crushed and hopeless. The rich array of unit types and... | Read more »
Collect pets and sling arrows in Arcane...
Mobile gaming is a crowded market, but regular updates are a good way to keep us attention-short players keen. The brand new content in Arcane Online is a prime example. Published by Japanese developer Gala, Arcane Online is a fantasy MMO that... | Read more »
Super Mario Run dashes onto Android in M...
Super Mario Run was one of the biggest mobile launches in 2016 before it was met with a lukewarm response by many. While the game itself plays a treat, it's pretty hard to swallow the steep price for the full game. With that said, Android users... | Read more »
WarFriends Beginner's Guide: How to...
Chillingo's new game, WarFriends, is finally available world wide, and so far it's a refreshing change from common mobile game trends. The game's a mix of tower defense, third person shooter, and collectible card game. There's a lot to unpack here... | Read more »
Super Gridland (Entertainment)
Super Gridland 1.0 Device: iOS Universal Category: Entertainment Price: $1.99, Version: 1.0 (iTunes) Description: Match. Build. Survive. "exquisitely tuned" - Rock Paper Shotgun No in-app purches, and no ads! | Read more »
Red's Kingdom (Games)
Red's Kingdom 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Mad King Mac has kidnapped your father and stolen your golden nut! Solve puzzles and battle goons as you explore and battle your... | Read more »
Turbo League Guide: How to tame the cont...
| Read more »
Fire Emblem: Heroes coming to Google Pla...
Nintendo gave us our first look at Fire Emblem: Heroes, the upcoming mobile Fire Emblem game the company hinted at last year. Revealed at the Fire Emblem Direct event held today, the game will condense the series' tactical RPG combat into bite-... | Read more »
ReSlice (Music)
ReSlice 1.0 Device: iOS Universal Category: Music Price: $9.99, Version: 1.0 (iTunes) Description: Audio Slice Machine Slice your audio samples with ReSlice and create flexible musical atoms which can be triggered by MIDI notes or... | Read more »

Price Scanner via MacPrices.net

Deal alert! 13-inch 2.0GHz MacBook Pros for $...
B&H Photo has the new 2016 13″ 2.0GHz non-Touch Bar MacBook Pros in stock today and on sale for $225 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.0GHz MacBook Pro... Read more
Free LibreOffice Portable 5.2.4 Complete Offi...
PortableApps.com and The Document Foundation have announce the release of LibreOffice Portable 5.2.4. LibreOffice Portable is an Open Source full-featured office suite — including a word processor,... Read more
Apple Planning Three New Tablets For 2017 – D...
Digitimes’ Rebecca Kuo and Joseph Tsai say that unnamed insider sources report Apple having three new tablets in the pipeline for 2017 release: a 9.7-inch model with a friendly price range, a new mid... Read more
Roundup of 15-inch Touch Bar MacBook Pro sale...
B&H Photo has the new 2016 15″ Apple Touch Bar MacBook Pros in stock today and on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.7GHz Touch Bar... Read more
Apple refurbished iPad Pros available for up...
Apple has Certified Refurbished 9″ and 12″ Apple iPad Pros available for up to $160 off the cost of new iPads. An Apple one-year warranty is included with each model, and shipping is free: - 32GB 9″... Read more
16GB iPad Air 2, Apple refurbished, available...
Apple has Certified Refurbished 16GB iPad Air 2s available for $319 including free shipping. A standard Apple one-year is included. Their price is $60 off original MSRP for this model. Read more
Apple iMacs on sale for up to $120 off MSRP
B&H Photo has 21″ and 27″ Apple iMacs on sale for up to $120 off MSRP, each including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2199 $100 off MSRP - 27″ 3.2GHz/1TB Fusion iMac... Read more
Apple refurbished Apple TVs available for up...
Apple has Certified Refurbished 32GB and 64GB Apple TVs available for up to $30 off the cost of new models. Apple’s standard one-year warranty is included with each model, and shipping is free: -... Read more
Save up to $350 with Apple Certified Refurbis...
Apple has Certified Refurbished 2015 21″ & 27″ iMacs available for up to $350 off MSRP. Apple’s one-year warranty is standard, and shipping is free. The following models are available: - 21″ 3.... Read more
2015 12-inch Retina MacBooks, Apple refurbish...
Apple has Certified Refurbished 2015 12″ Retina MacBooks available for up to $410 off original MSRP. Apple will include a standard one-year warranty with each MacBook, and shipping is free. The... Read more

Jobs Board

*Apple* & PC Desktop Support Technician...
Apple & PC Desktop Support Technician job in Manhattan, NY Introduction: We have immediate job openings for several Desktop Support Technicians with one of our most Read more
*Apple* & PC Desktop Support Technician...
Apple & PC Desktop Support Technician job in Stamford, CT We have immediate job openings for several Desktop Support Technicians with one of our most well-known Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Site Security Manager - Apple (Unite...
# Apple Site Security Manager Job Number: 54692472 Culver City, California, United States Posted: Jan. 19, 2017 Weekly Hours: 40.00 **Job Summary** The Apple Read more
*Apple* macOS Systems Integration Administra...
…most exceptional support available in the industry. SCI is seeking an Junior Apple macOS systems integration administrator that will be responsible for providing Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.