<p>You are given a string <code>s</code>. An <strong>awesome</strong> substring is a non-empty substring of <code>s</code> such that we can make any number of swaps in order to make it a palindrome.</p>

<p>Return <em>the length of the maximum length <strong>awesome substring</strong> of</em> <code>s</code>.</p>

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

<pre>
<strong>Input:</strong> s = &quot;3242415&quot;
<strong>Output:</strong> 5
<strong>Explanation:</strong> &quot;24241&quot; is the longest awesome substring, we can form the palindrome &quot;24142&quot; with some swaps.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;12345678&quot;
<strong>Output:</strong> 1
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;213123&quot;
<strong>Output:</strong> 6
<strong>Explanation:</strong> &quot;213123&quot; is the longest awesome substring, we can form the palindrome &quot;231132&quot; with some swaps.
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
	<li><code>s</code> consists only of digits.</li>
</ul>

class Solution {
public:
    // all evens except one
    // all evens
    // we can represent even/odd with string "10010101001"
    
    int longestAwesome(string s) {
        
        int res = 0;
        vector<int> count(10, 0);
        unordered_map<string, int> seen;
        seen["0000000000"] = -1;
        
        for (int i = 0; i < s.length(); i++){
            char c = s[i];
            count[c-'0']++;

            string curr = "";
            for (int v : count){
                if (v%2){
                    curr += '1';
                } else {
                    curr += '0';
                }
            }
            for (int j = 0; j < 10; j++){
                string newstr = curr;
                if(curr[j] == '1'){
                    newstr[j] = '0';
                } else {
                    newstr[j] = '1';
                }

                if (seen.find(newstr) != seen.end()){
                    res = max(res, i-seen[newstr]);
                }
            }
            if (seen.find(curr) != seen.end()){
                res = max(res, i-seen[curr]);
            } else {
                seen[curr] = i;
            }
        }
        return res;
    }
};
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