Online PHP editor | refs for PFQ5d

<?php // https://stackoverflow.com/questions/55137231 $cases = [ [[], false], [[1], false], [[1,2], false], [[1,3], true], [[1,2,3], false], [[1,2,4], true], [[2,3,5,6], true], [[2,5,6,8], false], [[3,6,10,16], false], [[5,7,8,9,10,11], true], ]; // Assuming zero indexed and sequential keys in array. function missing_only_one_incremental_value_in_sequence(array $nums) { $count = count($nums); $seq_count = 0; for($i=1; $i<$count; $i++) if($nums[$i]==$nums[$i-1]+1) $seq_count++; return $seq_count == $count-2; } foreach($cases as $case) { echo implode(',', $case[0]); echo "\n"; $result = missing_only_one_incremental_value_in_sequence($case[0]); var_dump($result); echo $result == $case[1] ? 'Pass' : 'Fail'; echo "\n\n"; }