<?php//背包01问题class Item{    public $weight;    public $value;    public function __construct($weight,$value){        $this->weight = $weight;        $this->value = http://www.mamicode.com/$value;    }}class Bag{    private $items;    public function __construct($items){        $this->items = $items;    }    private  $resultMap = array();    function bestBag($k,$w){        if($k==0 || $w==0){            return 0;        }        if(isset($this->resultMap[$k][$w])){            return $this->resultMap[$k][$w];        }        if($k==1) {            if ($this->items[$k]->weight > $w) {                return 0;            } else {                return $this->items[$k]->value;            }        }        $res1 = $this->bestBag($k-1,$w);        if($w-$this->items[$k]->weight>0){            $res2 = $this->bestBag($k-1,$w-$this->items[$k]->weight)+$this->items[$k]->value;        }else{            $res2 = 0;        }        $result = max($res1,$res2);        if(!isset($this->resultMap[$k][$w])){            $this->resultMap[$k][$w] = $result;        }        return $result;    }}$items = array();for($i = 1;$i<6;$i++){    $item = new Item($i,$i+3);    $items[$i] = $item;}print_r($items);$bagTest = new Bag($items);echo $bagTest->bestBag(5,60);exit;