<p>You are given an alphanumeric string <code>s</code>. (<strong>Alphanumeric string</strong> is a string consisting of lowercase English letters and digits).</p>

<p>You have to find a permutation of the string where no letter is followed by another letter and no digit is followed by another digit. That is, no two adjacent characters have the same type.</p>

<p>Return <em>the reformatted string</em> or return <strong>an empty string</strong> if it is impossible to reformat the string.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;a0b1c2&quot;
<strong>Output:</strong> &quot;0a1b2c&quot;
<strong>Explanation:</strong> No two adjacent characters have the same type in &quot;0a1b2c&quot;. &quot;a0b1c2&quot;, &quot;0a1b2c&quot;, &quot;0c2a1b&quot; are also valid permutations.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;leetcode&quot;
<strong>Output:</strong> &quot;&quot;
<strong>Explanation:</strong> &quot;leetcode&quot; has only characters so we cannot separate them by digits.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;1229857369&quot;
<strong>Output:</strong> &quot;&quot;
<strong>Explanation:</strong> &quot;1229857369&quot; has only digits so we cannot separate them by characters.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 500</code></li>
	<li><code>s</code> consists of only lowercase English letters and/or digits.</li>
</ul>

class Solution {
public:
    string reformat(string s) {
        vector<int> numbers;
        vector<char> characters;

        for(auto var : s){
            if (isdigit(var)){
                numbers.push_back(int(var));
            }
            else{
                characters.push_back(var);
            }
        }

       if (!arraySizeDiff(numbers, characters)){
            return "";
       }

        string output = "";
        bool digit = numbers.size() > characters.size() ? true : false;

        auto numIt = numbers.begin();
        auto charIt = characters.begin();

        while(numIt < numbers.end() && charIt < characters.end()){
            if (digit){
                output += *numIt;
                numIt++;
                digit = false;
            }
            else{
                output += *charIt;
                charIt++;
                digit = true;
            }
        }

        digit ? output += *numIt : output += *charIt;

        return output;

    }

    template <typename T, typename U>
    bool arraySizeDiff(vector<T> arr1, vector<U> arr2){
        if (arr1.size() == arr2.size()){
            return true;
        }

        if (arr1.size() > arr2.size()){
            return (arr1.size() - arr2.size()) == 1 ? true : false;
        }
        else{
            return (arr2.size() - arr1.size()) == 1 ? true : false;
        }
    }
};
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