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<?php //Our recursive function. function recursive($str, $count, $start, &$duplicate){ //Print out the number. if($count > $start) { if(!isset($duplicate[$str[$start]])) { $duplicate[$str[$start]] = 1; return recursive($str, $count, $start+1, $duplicate); } else { //array_push($duplicate, array($start=>$str[$start])); $duplicate[$str[$start]] +=1; return recursive($str, $count, $start+1, $duplicate); } } } //Set our start number to 1. $str = 'buffet'; $count = strlen($str); $start = 0; $duplicate = array(); //Call our recursive function. recursive($str, $count, $start, $duplicate); print_r($duplicate);
Output for 7.1.25 - 7.1.30, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Array ( [b] => 1 [u] => 1 [f] => 2 [e] => 1 [t] => 1 )

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