Eight Queens Problem - JavaScriptSource

This is a JavaScript that involves the movement of the Queen in Chess. Simply place eight queens on a chess board without conflict.
<!– ONE STEP TO INSTALL EIGHT QUEENS PROBLEM:

  1.  Copy the coding into the BODY of your HTML document  –>

<!– STEP ONE: Paste this code into the BODY of your HTML document  –>

<BODY>

<!– This script and many more are available free online at –>

<!– The JavaScript Source!! http://javascript.internet.com –>

<!– Original:  Ronald Daenzer ([email protected]) –>

<!– Web Site:  http://as400.ferris.edu/daer/EightQueensProb.htm –>

<form name=myform>



<div align=center>



<h1>Eight Queens problem</h1>



Place eight queens on chess board without conflict<br>



<table border=1 width=300 height=300 style=cursor:hand>



<script>

//eight queens problem

//ron daenzer



var closed = new Array(64);



var imgQueen = new Image(32,32);

var imgEmpty = new Image(32,32);

var imgDot = new Image(32,32);

var id=0;

var count=0;



imgQueen.src = “queen.gif”;

imgEmpty.src = “empty.gif”;

imgDot.src = “dot.gif”;



for (var r=0; r<8; r++)    //8 rows

{

  document.write(‘<tr>’);

  for (var c=0; c<8; c++)  //8 columns

  {

    id=(r*8)+c;            //calculate cell id

    document.write(‘<td id=’+id+’ onclick=”placeq(this);”>’);

    document.write(‘<img src=”empty.gif”></td>’);

  }

  document.write(‘</tr>’);

}



function placeq (cell)

{

  var q = eval(cell.id);

  var r = Math.floor(q /8);

  var c = q % 8;

  var min = Math.min(r,c);

  var max = Math.max(r,c);



  if ( (document.images[q].src == imgEmpty.src) && (safe(q)) )

  {

    //document.images[q].src = imgQueen.src;

    count++;

    for (var h=r*8; h<(r*8)+8; h++)

    { closed[h]=h; document.images[h].src=imgDot.src; }



    for (var v=c; v<64; v=v+8)

    { closed[v]=v; document.images[v].src=imgDot.src; }



    if (c>r) { var x1=c-r; var x2=q+(9*(8-c)); }

    else { var x1=(r-c)*8; var x2=q+(9*(8-r)); }

    for (var x=x1; x<x2; x=x+9)

    { closed[x]=x; document.images[x].src=imgDot.src; }



    if (r+c>7) { var y1=q-((7-c)*7); var y2=q+(7*(8-r)); }

    else { var y1=r+c; var y2=q+(8*c); }

    for (var y=y1; y<y2; y=y+7)

    { closed[y]=y; document.images[y].src=imgDot.src; }



    document.images[q].src = imgQueen.src;

  }

  if (count == 8)

    alert(“Good job, you solved it!”);

  if (count > 8)

    alert(“Too many queens”);

}



function safe (q)

{ //safe position to place queen on board

  if ( closed[q]==q )

    return false;

  else

    return true;

}



function help ()

{ //help print an example of 8 queens

  var a = new Array(0,12,23,29,34,46,49,59);

  clearBoard();

  for (var i=0; i<8; i++)

    window.document.images[ a[i] ].src = imgQueen.src;

  count=8;

  for (var q=0; q<64; q++)

    closed[q] = q;

}



function clearBoard ()

{ //clear the image array

  for (var i=0; i<64; i++)

    window.document.images[i].src = imgEmpty.src;

  count=0;

  closed = new Array(64);

}



</script>



</table>

<input type=button value=” clear ” onclick=”clearBoard()”>

<input type=button value=” help ” onclick=”help()”>



</div>

</form>



<p><center>

<font face=”arial, helvetica” size”-2″>Free JavaScripts provided<br>

by <a href=”https://javascriptsource.com”>The JavaScript Source</a></font>

</center><p>
Related Snippets:
