数组算法解决思路

数组算法
Array
(
  [0] => Array
  (
  [0] => 1
  [1] => 2
  )

  [1] => Array
  (
  [0] => 2
  [1] => 2
  )

  [2] => Array
  (
  [0] => 1
  [1] => 2
  )

  [3] => Array
  (
  [0] => 2
  [1] => 3
  )

  [4] => Array
  (
  [0] => 3
  [1] => 2
  )

  [5] => Array
  (
  [0] => 2
  [1] => 2
  )

  [6] => Array
  (
  [0] => 2
  [1] => 2
  )

  [7] => Array
  (
  [0] => 2
  [1] => 2
  )

  [8] => Array
  (
  [0] => 2
  [1] => 2
  )

  [9] => Array
  (
  [0] => 3
  [1] => 2
  )

  [10] => Array
  (
  [0] => 2
  [1] => 3
  )

  [11] => Array
  (
  [0] => 20
  [1] => 30
  )

  [12] => Array
  (
  [0] => 35
  [1] => 25
  )

  [13] => Array
  (
  [0] => 100
  [1] => 15
  )
  [14] => Array
  (
  [0] => 2
  [1] => 1
  )

)
目的：里面有重复的只保留一个，然后数据是全部都是唯一的。倒过来的也认为是重复的，譬如1,2和2,1也当作是重复的。。
自己写了个算法。觉得效率太慢了。。大家还有好的算法不？

------解决方案--------------------
array_unique()
------解决方案--------------------
foreach($inputarray as $value) {
foreach($value as $key=>$v) {
$newarray[$v] = $key;
}
}
$array = array_keys($newarray);
print_r($array);