number_combinations

<?php
/**
 * Created by PhpStorm.
 * User: dabiddo
 * Date: 11/5/2018
 * Time: 11:53 AM
 * Create posible combinations of a secuence of numbers
 */
function solution($N) {
    
    $length=strlen($N)-1;

    $arrNumbers = str_split($N);

    $totalCombinations =0;

    for($x=0;$x<=$length;$x++)
    {
        $leading = $arrNumbers[$x];
        $newArray = $arrNumbers;
        unset($newArray[$x]);
        $newArray=array_values($newArray);
        $totalCombinations += combine($leading,$newArray);
        //var_dump($totalCombinations);
        //array_merge($totalCombinations,combine($leading,$newArray));
    }

    return $totalCombinations;

}

function combine($leading,$arrleft){
    $newLeng=count($arrleft);
    $combiArray = [];
    $rounds = 0;

    while ($rounds!=$newLeng){
        $leadingNo=$leading;
        foreach ($arrleft as $number){
            $leadingNo.=$number;
        }

        array_push($combiArray,$leadingNo);

        if($rounds<$newLeng-1){
            $index = $arrleft[$rounds];
            $sindex = $arrleft[$rounds+1];

            $arrleft[$rounds]=$sindex;
            $arrleft[$rounds+1]=$index;
        }

        $rounds++;
    }
    //var_dump($combiArray);
    return count($combiArray);
}

echo(solution(1213));