<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 {
public:
    int lengthOfLongestSubstring(string s) {
        if(s.length() == 0)
            return 0;
        
        // Mega brute force method. 
        // - Other ppl use sliding window, could be interesting to look into at further date (if I remember to LOL).
        int longest = 1;
        int maxLength = s.length();
        for(int i = 0; i < maxLength; ++i) {
            std::vector<char> encountered;
            encountered.reserve(maxLength); // nasty, but reserve max length of string to prevent resizing ops on vector. disgoosting.
            int length = 0;
            for(int n = i; n < maxLength; ++n) {
                if(std::count(encountered.begin(), encountered.end(), s[n]) == 0) {
                    ++length;
                    encountered.emplace_back(s[n]);
                }
                else {
                    break;
                }
            }
            longest = std::max(length, longest);
        }

        return longest;
    }
};
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