<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>

#include <iostream>
#include <queue>
#include <string>
using namespace std;

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        queue<char> q;  // Queue to store the current substring
        int max_length = 0;

        for (char c : s) {
            // Check if the character is already in the queue by iterating over it
            while (isInQueue(q, c)) {
                q.pop();  // Remove the front character until the duplicate is removed
            }
            q.push(c);  // Add the current character to the queue
            max_length = max(max_length, (int)q.size());  // Update the max length
        }

        return max_length;
    }

private:
    bool isInQueue(queue<char> q, char c) {
        while (!q.empty()) {
            if (q.front() == c) {
                return true;  // Character found in the queue
            }
            q.pop();  // Remove front element and continue searching
        }
        return false;  // Character not found
    }
};
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