Remove duplicate result from Permutation Function PHP if input contain same char

Question

Actually this code working, but if input contain same char the result have a duplicate. This code i found here, but i cant find the solution to remove duplicate result when i try it self.

Here's the PHP code with an example

function getPermCount($letters, $count)
{
  $result = 1;

  for($i = strlen($letters) - $count + 1; $i <= strlen($letters); $i++) {
    $result *= $i;
 }
  return $result;
}


function getPerm($letters, $count, $index)
{
  $result = '';
  for($i = 0; $i < $count; $i++)
  {
    $pos = $index % strlen($letters);
    $result .= $letters[$pos];
    $index = ($index-$pos)/strlen($letters);
    $letters = substr($letters, 0, $pos) . substr($letters, $pos+1);

  }

  return $result; 

For the example

$letters = 'abcc';
$cek = 2;

for($i = 0; $i < getPermCount($letters, $cek); $i++) {

    $gege =  getPerm($letters, $cek, $i).","; 
    echo $gege;
    }

result

ab,ba,ca,ca,ac,bc,cb,cb,ac,bc,cc,cc,

I want the duplicate result removed, exactly like this

ab,ba,ca,ac,bc,cb,cc,

Answer 1

You can pass your result to an array and then remove the duplicated ones and pass back to string.

First you use explode() on your string to create an array using the , as separator:

$array = explode(",", $gege)

Then you can use array_unique() to remove duplicated values from the array:

$array_unique = array_unique($array);

When you have the array with unique values you just need to transform it back to string, you can use implode() and indicate , as a separator again for it:

$unique_string = implode("," $array_unique);

Fast example:

$gege = "ab,ba,ca,ca,ac,bc,cb,cb,ac,bc,cc,cc,";

echo implode(",",array_unique(explode(",", $gege)));

You can create a function to do it:

function stringUnique($string, $separator){

  return implode($separator,array_unique(explode($separator, $string)));

}

Then after your permutation you can just run the function like this:

$gege = "";
for($i = 0; $i < getPermCount($letters, $cek); $i++) {
    $gege .=  getPerm($letters, $cek, $i).","; 
}
echo stringUnique($gege, ",");