942. DI String Match

Title Link

942. DI String Match

Title Analysis

Given a string S containing only I and D, an array is returned.
This number satisfies the following conditions:
When S[i] is I, A [i] < A [i + 1]. The latter number is larger than the former.
When S[i] is D, A [i] > A [i + 1]. The number in front is bigger than that in the back.

thinking

Loop through a given string.
When I is encountered, the subscript of the current letter is inserted directly behind the array.
When D is encountered, the current subscript is inserted before the current subscript position of the array.

Final code

<?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;
                                                                                                                                                                                                           }
                                                                                                                                                                                                           }

                                                                                                                                                                                                       
                                                                                                                                                                                                       Personally, I don't think this is a very good description. When you have time, you will try to describe the problem clearly.
                                                                                                                                                                                                       
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