Original text
Description
Given a string s, find the length of the longest substring without
repeating characters.
Example 1
Input:
s = "abcabcbb"Output:
3Explanation:
The answer is "abc", with the length of 3.
Example 2
Input:
s = "bbbbb"Output:
1Explanation:
The answer is "b", with the length of 1.
Example 3
Input:
s = "pwwkew"Output:
3Explanation:
The answer is "wke", with the length of 3. Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.
Constraints
0 <= s.length <= 5 * 10⁴sconsists of English letters, digits, symbols and spaces.
Solution (PHP 8.2)
function getLongestSubstringLength(string $input): int
{
$inputLength = \strlen($input);
$buffer = [];
$longestSubstringLength = 0;
for ($charIndex = 0; $charIndex < $inputLength; $charIndex++) {
$char = \substr($input, $charIndex, length: 1);
if (\in_array($char, $buffer)) {
$buffer = [$char];
continue;
}
$buffer[] = $char;
$bufferLength = \count($buffer);
if ($bufferLength > $longestSubstringLength) {
$longestSubstringLength = $bufferLength;
}
}
return $longestSubstringLength;
}
Debug
>> abcabcbb
3 abc
3 abc
1 b
1 b
<< 3
>> pwwkew
2 pw
3 wke
1 w
<< 3
>> Lorem ipsum dolor sit amet
10 Lorem ipsu
5 m dol
6 or sit
5 amet
<< 10
Tests
| Input string | Result | Time | Memory |
|---|---|---|---|
abcabcbb | 3 | 65μs | 792B |
bbbbb | 1 | 60μs | 576B |
pwwkew | 3 | 26μs | 648B |
Lorem ipsum dolor sit amet | 10 | 55μs | 2088B |
| 0 | 13μs | 56B |
1 | 1 | 61μs | 288B |
11 | 1 | 58μs | 360B |
OS: Ubuntu WSL2 (5.15.146.1-microsoft-standard-WSL2)
CPU: AMD Ryzen 7 5800X
RAM: 16GB
PHP 8.2.17 (cli) (built: Mar 16 2024 08:41:44) (NTS)
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