PHP greedy algorithm solves 0-1 knapsack problem example Analysis _php skill

This article describes the PHP greedy algorithm to solve the 0-1 knapsack problem method. Share to everyone for your reference. The specific analysis is as follows:

The greedy algorithm solves 0-1 knapsack problem, and the global optimal solution is obtained by local optimal solution. More flexible than dynamic planning to solve knapsack problem!

0-1 knapsack greedy algorithm problem class tanxin{public $weight;
  Public $price;
    Public function __construct ($weight =0, $price =0) {$this->weight= $weight;
  $this->price= $price;
}//Generate Data $n = 10;
  for ($i =1; $i <= $n; $i + +) {$weight =rand (1,20);
  $price =rand (1,10);
$x [$i]=new tanxin ($weight, $price);
  //Output result function display ($x) {$len =count ($x);
    foreach ($x as $val) {echo $val->weight, ', $val->price;
  Echo ' <br> ';
  }//ORDER by price and weight ratio tsort (& $x) {$len =count ($x);
      For ($i =1 $i <= $len $i + +) {for ($j =1; $j <= $len-$i; $j + +) {$temp = $x [$j];
      $res = $x [$j +1]->price/$x [$j +1]->weight;
      $temres = $temp->price/$temp->weight;
        if ($res > $temres) {$x [$j]= $x [$j +1];
      $x [$j +1]= $temp;
  }}//greedy algorithm function tanxin ($x, $totalweight =50) {$len =count ($x);
  $allprice = 0;
    For ($i =1 $i <= $len $i + +) {if ($x [$i]->weight> $totalweight) break;
  else{$allprice + + $x [$i]->price;    $totalweight = $totalweight-$x [$i]->weight;
  } if ($i < $len) $allprice + = $x [$i]->price* ($totalweight/$x [$i]->weight);
return $allprice;
Tsort ($x);//order display ($x) in a non increment order;//show Echo ' 0-1 The best solution is: '; echo tanxin ($x);

I hope this article will help you with your PHP programming.