ทำยังไงถึงจะเก็บเป็นเลขทศนิยมได้ค่ะ PHP class Dijkstra { var $visited = array(); var $dista
<?PHP
class Dijkstra {
var $visited = array();
var $distance = array();
var $previousNode = array();
var $startnode =null;
var $map = array();
var $infiniteDistance = 0;
var $numberOfNodes = 0;
var $bestPath = 0;
var $matrixWidth = 0;
function Dijkstra(&$ourMap, $infiniteDistance) {
$this -> infiniteDistance = $infiniteDistance;
$this -> map = &$ourMap;
$this -> numberOfNodes = count($ourMap);
$this -> bestPath = 0;
}
function findShortestPath($start,$to = null) {
$this -> startnode = $start;
for ($i=0;$i<$this -> numberOfNodes;$i++) {
if ($i == $this -> startnode) {
$this -> visited[$i] = true;
$this -> distance[$i] = 0;
} else {
$this -> visited[$i] = false;
$this -> distance[$i] = isset($this -> map[$this -> startnode][$i])
? $this -> map[$this -> startnode][$i]
: $this -> infiniteDistance;
}
$this -> previousNode[$i] = $this -> startnode;
}
$maxTries = $this -> numberOfNodes;
$tries = 0;
while (in_array(false,$this -> visited,true) && $tries <= $maxTries) {
$this -> bestPath = $this->findBestPath($this->distance,array_keys($this -> visited,false,true));
if($to !== null && $this -> bestPath === $to) {
break;
}
$this -> updateDistanceAndPrevious($this -> bestPath);
$this -> visited[$this -> bestPath] = true;
$tries++;
}
}
function findBestPath($ourDistance, $ourNodesLeft) {
$bestPath = $this -> infiniteDistance;
$bestNode = 0;
for ($i = 0,$m=count($ourNodesLeft); $i < $m; $i++) {
if($ourDistance[$ourNodesLeft[$i]] < $bestPath) {
$bestPath = $ourDistance[$ourNodesLeft[$i]];
$bestNode = $ourNodesLeft[$i];
}
}
return $bestNode;
}
function updateDistanceAndPrevious($obp) {
for ($i=0;$i<$this -> numberOfNodes;$i++) {
if( (isset($this->map[$obp][$i]))
&& (!($this->map[$obp][$i] == $this->infiniteDistance) || ($this->map[$obp][$i] == 0 ))
&& (($this->distance[$obp] + $this->map[$obp][$i]) < $this -> distance[$i])
)
{
$this -> distance[$i] = $this -> distance[$obp] + $this -> map[$obp][$i];
$this -> previousNode[$i] = $obp;
}
}
}
function printMap(&$map) {
$placeholder = ' %' . strlen($this -> infiniteDistance) .'d';
$foo = '';
for($i=0,$im=count($map);$i<$im;$i++) {
for ($k=0,$m=$im;$k<$m;$k++) {
$foo.= sprintf($placeholder, isset($map[$i][$k]) ? $map[$i][$k] : $this -> infiniteDistance);
}
$foo.= "\n";
}
return $foo;
}
function getResults($to = null) {
$ourShortestPath = array();
$foo = '';
for ($i = 0; $i < $this -> numberOfNodes; $i++) {
if($to !== null && $to !== $i) {
continue;
}
$ourShortestPath[$i] = array();
$endNode = null;
$currNode = $i;
$ourShortestPath[$i][] = $i;
while ($endNode === null || $endNode != $this -> startnode) {
$ourShortestPath[$i][] = $this -> previousNode[$currNode];
$endNode = $this -> previousNode[$currNode];
$currNode = $this -> previousNode[$currNode];
}
$ourShortestPath[$i] = array_reverse($ourShortestPath[$i]);
if ($to === null || $to === $i) {
if($this -> distance[$i] >= $this -> infiniteDistance) {
$foo .= sprintf("no route from %d to %d. \n",$this -> startnode,$i);
} else {
$foo .= sprintf('%d => %d = %d [%d]: (%s).'."\n" ,
$this -> startnode,$i,$this -> distance[$i],
count($ourShortestPath[$i]),
implode('-',$ourShortestPath[$i]));
}
$foo .= str_repeat('-',20) . "\n";
if ($to === $i) {
break;
}
}
}
return $foo;
}
} // end class
?>
<?php
// I is the infinite distance.
define("I",1000);
// Size of the matrix
$matrixWidth = 10;
// $points is an array in the following format: (router1,router2,distance-between-them)
$points = array(
array("0","1","0"),
array("1","2","23"),
array("1","3","89"),
array("2","4","62"),
array("2","5","6"),
array("3","6","31"),
array("3","7","37"),
array("3","10","54"),
array("4","10","20"),
array("5","8","68"),
array("5","9","82"),
array("5","10","42"),
array("9","10","46"),
array("7","10","28"),
);
$ourMap = array();
// Read in the points and push them into the map
for ($i=0,$m=count($points); $i<$m; $i++) {
$x = $points[$i][0];
$y = $points[$i][1];
$c = $points[$i][2];
$ourMap[$x][$y] = $c;
$ourMap[$y][$x] = $c;
}
// ensure that the distance from a node to itself is always zero
// Purists may want to edit this bit out.
for ($i=0; $i < $matrixWidth; $i++) {
for ($k=0; $k < $matrixWidth; $k++) {
if ($i == $k) $ourMap[$i][$k] = 0;
}
}
// initialize the algorithm class
$dijkstra = new Dijkstra($ourMap, I,$matrixWidth);
// $dijkstra->findShortestPath(0,13); to find only path from field 0 to field 13...
$dijkstra->findShortestPath(0);
// Display the results
echo '<pre>';
echo "the map looks like:\n\n";
echo $dijkstra -> printMap($ourMap);
echo "\n\nthe shortest paths from point 0:\n";
echo $dijkstra -> getResults();
echo '</pre>';
?>Tag : - - - -
Date :
4 ก.ย. 2551 21:38:49
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