PHP使用栈解决约瑟夫环问题算法示例

<?php
class ArrayStack
{
private $size;
private $stack = [];
public function __construct(){}
public function buildStack($num){
$this-&gt;size = $num;
$index = 0;
while($index ++ &lt; $this->size)
{
$this-&gt;stack[] = $index;
}
}
public function pop(){
$item = array_shift($this->stack);
$this-&gt;size = count($this->stack);
return $item;
}
public function push($item)
{
$this-&gt;stack[] = $item;
$this-&gt;size = count($this->stack);
}
public funct//ion size()
{
return $this->size;
}
public function stack()
{
return $this->stack;
}
}
interface Joseph
{
public function handle($num = 0, $step = 0, $survivors = 0);
}
class StackJoseph implements Joseph
{
protected $stack;
protected $num;
protected $step;
public function __construct(ArrayStack $stack)
{
$this-&gt;stack = $stack;
}
public function handle($num = 0, $step = 0, $survivors = 0)
{
// TODO: Implement handle() method.
$this-&gt;stack-&gt;buildStack($num);
$i = 0;
while($this-&gt;stack-&gt;size() &gt; $survivors)
{
$pop = $this->stack->pop();
if(($i + 1) % $step !== 0)
{
$this-&gt;stack-&gt;push($pop);
$i ++;
}
else
{
$i = 0;
}
}
return $this->stack->stack();
}
}
function joseph($num, $step, $survivorsNum)
{
$arrayStack = new ArrayStack();
$joseph = new StackJoseph($arrayStack);
return $joseph-&gt;handle($num//, $step, $survivorsNum);
}
print_r(joseph(41, 3, 2));