Leetcode PHP题解--D10 942. DI String Match

<?php

class Solution {

    function diStringMatch($S) {

        $S = str_split($S);

        $n = range(0,count($S));

        $nums = [array_shift($n)];

        $currentPosition = 0;

        foreach($S as $s){

            if($s == 'I'){

                $nums[] = array_shift($n);

            }

            else{

                $left = ($currentPosition>=0 ?array_slice($nums,0,$currentPosition):[]);

                $right = ($currentPosition<count($nums)?array_slice($nums,$currentPosition):[]);

                $middle = [array_pop($n)];

                $nums = array_merge($left,$middle,$right);

            }

            $currentPosition++;

        }

       return $nums;

    }

}