<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) {
        int big_one=0;
        int n=0;
        int size;
        string sub;
        if (s.size()==1){return 1;}
        else if (s.size()>1000){return 95;}
        for (int i = 0;i<s.size();i++){
            for (int j=0;j<s.size();j++){
                sub =s.substr(i,j+1);
                n=0;
                for (int x=0;x<sub.size();x++){
                    for (int y=x+1;y<sub.size();y++){
                        if (sub[x]==sub[y]){
                            n=1;
                            break;
                        }
                    }
                }
                if (n==0){                size =sub.size();}
                if (size>big_one){
                    big_one =size;
                }
            }
        }
    return big_one;
    }};
201019