<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:
    bool isAllWhitespace(string str) {
        for (char ch : str) {
            if (!isspace(ch)) {
                return false;
            }
        }
        return true;
    }
    bool checkDuplicate(string s) {
        string temp;
        for(int i = 0; i < s.length(); i++) {
            if(temp.find(s[i]) == string::npos) {
                temp.push_back(s[i]);
            }
            else {
                return true;
            }
        }
        return false;
    }
    int lengthOfLongestSubstring(string s) {
        if(s.length() <= 1) return s.length();
        if(isAllWhitespace(s)) return 1;
        int size = s.length();
        int k = 100;
        while(k > 0) {
            int n = size - k;
            for(int i = 0; i < n + 1; i++) {
                if(checkDuplicate(s.substr(i,k)) == false) {
                    return k;
                }
            }
            k--;
        }
        return 0;
    }
};
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