PHP贪婪算法解决0-1背包问题实例分析

 //0-1背包贪心算法问题 class tanxin{ public $weight; public $price; public function __construct($weight=0,$price=0) { $this->weight=$weight; $this->price=$price; } } //生成数据 $n=10; for($i=1;$iweight,' ',$val->price; echo '<br>'; } } //按照价格和重量比排序 function tsort(&$x) { $len=count($x); for($i=1;$i<=$len;$i++) { for($j=1;$jprice/$x[$j+1]->weight; $temres=$temp->price/$temp->weight; if($res>$temres){ $x[$j]=$x[$j+1]; $x[$j+1]=$temp; } } } } //贪心算法 function tanxin($x,$totalweight=50) { $len=co<strong style="color:transparent">来源gaodai#ma#com搞@@代~&码网</strong>unt($x); $allprice=0; for($i=1;$iweight>$totalweight) break; else{ $allprice+=$x[$i]->price; $totalweight=$totalweight-$x[$i]->weight; } } if($iprice*($totalweight/$x[$i]->weight); return $allprice; } tsort($x);//按非递增次序排序 display($x);//显示 echo '0-1背包最优解为:'; echo tanxin($x);