<p>Given a string <code>s</code>, find the length of the <strong>longest</strong> <span data-keyword="substring-nonempty"><strong>substring</strong></span> without repeating characters.</p>

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

<pre>
<strong>Input:</strong> s = &quot;abcabcbb&quot;
<strong>Output:</strong> 3
<strong>Explanation:</strong> The answer is &quot;abc&quot;, with the length of 3.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;bbbbb&quot;
<strong>Output:</strong> 1
<strong>Explanation:</strong> The answer is &quot;b&quot;, with the length of 1.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;pwwkew&quot;
<strong>Output:</strong> 3
<strong>Explanation:</strong> The answer is &quot;wke&quot;, with the length of 3.
Notice that the answer must be a substring, &quot;pwke&quot; is a subsequence and not a substring.
</pre>

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

<ul>
	<li><code>0 &lt;= s.length &lt;= 5 * 10<sup>4</sup></code></li>
	<li><code>s</code> consists of English letters, digits, symbols and spaces.</li>
</ul>

class Solution {
private:
bool find(queue<char>q,char x)
{
    while(q.size())
    {
        if(q.front()!=x)
        q.pop();
        if(q.front()==x)
        return true;
    }
    return false;
}
public:
    int lengthOfLongestSubstring(string s) {
        int len=0,curr=0;
        queue<char>q;
        for(int i=0;i<s.size();i++)
        {
            if(find(q,s[i]))
            {
                while(q.front()!=s[i])
                q.pop();
                q.pop();
                q.push(s[i]);
            }
            else
            {
                q.push(s[i]);
            }
            curr=q.size();
            len=max(len,curr);
        }
        curr=q.size();
        return len=max(len,curr);
    }
};
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