数据结构&算法(PHP描述) 三元组 Triplet

<?php
/**
 * 三元组 Triplet
 */
class Triplet
{
    private $_data = null; 
    // 初始化三元组
    public function init($val1, $val2, $val3)
    {
        $this -> _data[0] = $val1;
        $this -> _data[1] = $val2;
        $this -> _data[2] = $val3;
        return true;
    } 
    // 销毁三元组
    public function destroy()
    {
        unset($this -> _data);
        return true;
    } 
    // 返回第$key的值
    public function get($key)
    {
        if ($key < 1 || $key > 3) return false;
        return$this -> _data[$key-1];
    } 
    // 设置第$key元的值为$val
    public function put($key, $val)
    {
        if ($key < 1 || $key > 3) return false;
        $this -> _data[$key-1] = $val;
        return true;
    } 
    // 是否按升序排序
    public function isAscending()
    {
        return ($this -> _data[0] <= $this -> _data[1]) && ($this -> _data[1] <= $this -> _data[2]);
    } 
    // 是否按降序排序
    public function isDescending()
    {
        return ($this -> _data[0] >= $this -> _data[1]) && ($this -> _data[1] >= $this -> _data[2]);
    } 
    // 获取最大值
    public function max()
    {
        return ($this -> _data[0] >= $this -> _data[1])? ($this -> _data[0] >= $this -> _data[2])?$this -> _data[0] :$this -> _data[2] : ($this -> _data[1] >= $this -> _data[2])?$this -> _data[1] :$this -> _data[2];
    } 
    // 获取最小值
    public function min()
    {
        return ($this -> _data[0] <= $this -> _data[1])? ($this -> _data[0] <= $this -> _data[2])?$this -> _data[0] :$this -> _data[2] : ($this -> _data[1] <= $this -> _data[2])?$this -> _data[1] :$this -> _data[2];
    } 
} 

$objTriplet = new Triplet();
echo"init:";
var_dump($objTriplet -> init(1, 2, 3));
echo"<br/>";

echo"get 1:";
var_dump($objTriplet -> get(1));
echo"<br/>";
echo"get 4:";
var_dump($objTriplet -> get(4));
echo"<br/>"; // false
echo"put 3,4:";
var_dump($objTriplet -> put(3, 4));
echo"<br/>";

echo"max:";
var_dump($objTriplet -> max());
echo"<br/>";
echo"min:";
var_dump($objTriplet -> min());
echo"<br/>";

echo"isAscending:";
var_dump($objTriplet -> isAscending());
echo"<br/>";
echo"isDescending:";
var_dump($objTriplet -> isDescending());
echo"<br/>";

?>