Merge pull request #1342 from fmtvar/0028

添加(0028.实现strStr.md):PHP版本
This commit is contained in:
程序员Carl
2022-06-06 11:40:17 +08:00
committed by GitHub

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@ -1166,5 +1166,80 @@ func strStr(_ haystack: String, _ needle: String) -> Int {
```
PHP
> 前缀表统一减一
```php
function strStr($haystack, $needle) {
if (strlen($needle) == 0) return 0;
$next= [];
$this->getNext($next,$needle);
$j = -1;
for ($i = 0;$i < strlen($haystack); $i++) { // 注意i就从0开始
while($j >= 0 && $haystack[$i] != $needle[$j + 1]) {
$j = $next[$j];
}
if ($haystack[$i] == $needle[$j + 1]) {
$j++;
}
if ($j == (strlen($needle) - 1) ) {
return ($i - strlen($needle) + 1);
}
}
return -1;
}
function getNext(&$next, $s){
$j = -1;
$next[0] = $j;
for($i = 1; $i < strlen($s); $i++) { // 注意i从1开始
while ($j >= 0 && $s[$i] != $s[$j + 1]) {
$j = $next[$j];
}
if ($s[$i] == $s[$j + 1]) {
$j++;
}
$next[$i] = $j;
}
}
```
> 前缀表统一不减一
```php
function strStr($haystack, $needle) {
if (strlen($needle) == 0) return 0;
$next= [];
$this->getNext($next,$needle);
$j = 0;
for ($i = 0;$i < strlen($haystack); $i++) { // 注意i就从0开始
while($j > 0 && $haystack[$i] != $needle[$j]) {
$j = $next[$j-1];
}
if ($haystack[$i] == $needle[$j]) {
$j++;
}
if ($j == strlen($needle)) {
return ($i - strlen($needle) + 1);
}
}
return -1;
}
function getNext(&$next, $s){
$j = 0;
$next[0] = $j;
for($i = 1; $i < strlen($s); $i++) { // 注意i从1开始
while ($j > 0 && $s[$i] != $s[$j]) {
$j = $next[$j-1];
}
if ($s[$i] == $s[$j]) {
$j++;
}
$next[$i] = $j;
}
}
```
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