Example
Input: "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.
时间复杂度: O(N)- 空间复杂度: O(N)
print_r(test("abcabcbb"));
function test($str) {
if (empty($str)) {
return 0;
}
$strlen = mb_strlen($str);
$res = $start = $end = 0;
$lookup = [];
while ($start < $strlen && $end < $strlen) {
$nowStr = $str[$end];
if (in_array($nowStr,$lookup)) {
$deleStr = substr($str,0,$start);
$lookup = array_diff($lookup,[$deleStr]);
$start ++;
} else {
$lookup[] = $nowStr;
$res = max($res, $end-$start+1);
$end ++;
}
}
return $res;
}
