Print all combination of sub range within a given array - php

Question

I want to print all combination of sub range in an given array. I have an array of y number of elements in it from which I want to print all combination of contiguous sub range.
Constraint is : each sub range should have at least 2 elements and each element in sub range should be contiguous. It should share same border of each element.
For example, We have an array of 7 elements [11,12,13,14,11,12,13]
So, the total number of sub range combination will [7 * (7-1) /2] = 21
So, the Output will be something like this:
11,12
12,13
13,14
14,11
11,12
12,13
11,12,13
12,13,14
13,14,11
...
11,12,13,14 and so on (total 21 combination as per above array)
we should not print any combination which is not contiguous. example: [11,12,14] is not valid combination as it skips the element "13" in between.
I am able to print the combination with 2 elements but i am having difficulty in printing more then 2 elements combination.
Below is what I have tried so far.
$data=array("11","12","13","14","11","12","13");
$totalCount=count($data);
for($i=0;$i<$totalCount;$i++){
if(($i+1) < ($totalCount)){
echo "[".$data[$i].",".$data[$i+1]."]<br>";
}
}

Answer 1

You can do that:
$arr = [11,12,13,14,11,12,13];
function genComb($arr, $from = 1, $to = -1) {
$arraySize = count($arr);
if ($to == -1) $to = $arraySize;
$sizeLimit = $to + 1;
for ($i = $from; $i < $sizeLimit; $i++) { // size loop
$indexLimit = $arraySize - $i + 1;
for ($j = 0; $j < $indexLimit; $j++) { // position loop
yield array_slice($arr, $j, $i);
}
}
}
$count = 0;
foreach (genComb($arr, 2) as $item) {
echo implode(',', $item), PHP_EOL;
$count++;
}
echo "total: $count\n";

Answer 2

Casimir et Hippolyte was faster, but you can gain huge performance by processing each contiguous section independently:
function getCombos(&$data) {
$combos = array();
$count = count($data);
$i = 0;
while ($i < $count) {
$start = $i++;
while ($i < $count && $data[$i - 1] + 1 == $data[$i]) // look for contiguous items
$i++;
if ($i - $start > 1) // only add if there are at least 2
addCombos($data, $start, $i, $combos); // see other answer
}
return $combos;
}