Given a string, find the length of the **longest substring** without repeating characters.

**Example 1:**

Input:"abcabcbb"Output:3Explanation:The answer is`"abc"`

, with the length of 3.

**Example 2:**

Input:"bbbbb"Output:1Explanation:The answer is`"b"`

, with the length of 1.

**Example 3:**

Input:"pwwkew"Output:3Explanation:The answer is`"wke"`

, with the length of 3. Note that the answer must be asubstring,`"pwke"`

is asubsequenceand not a substring.

PHPcode :

```
class Solution {
function lengthOfLongestSubstring($s) {
$tmp = [];
$max = 0;
for($i=0;$i< strlen($s); $i++){
$k = array_search($s[$i], $tmp);
if($k !== false){
array_splice($tmp, 0, $k+1);
}
$tmp[] = $s[$i];
$max = $max > count($tmp) ? $max: count($tmp);
}
return $max;
}
}
```