<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:
    int longestAwesome(string s) {
        int mask = 0;
        map<int,int> maskPos;
        maskPos[mask] = -1;

        int n = s.length();

        int maxLen = 1;

        for(int i=0;i<n;i++){
            mask = mask ^ (1<<(s[i] - '0'));

            if(maskPos.find(mask)!=maskPos.end()){
                cout<<i<<" "<<mask<<" "<<maskPos[mask]<<endl;
                maxLen = max(maxLen, i - maskPos[mask]);
            }

            for(int j=0;j<10;j++){
                int tempMask = (mask ^ (1<<j));
                if(maskPos.find(tempMask)!=maskPos.end()){
                    maxLen = max(maxLen, i - maskPos[tempMask]);
                } 
            }
            if(maskPos.find(mask)==maskPos.end()){
                maskPos[mask] =  i;
            }
        }

        return maxLen;     
    }
};
15000