添加 0209.长度最小的子数组 PHP版本

problems/0209.长度最小的子数组.md

@@ -264,6 +264,34 @@ impl Solution {
 }
 ```
 
+PHP:
+```php
+// 双指针 - 滑动窗口
+class Solution {
+    /**
+     * @param Integer $target
+     * @param Integer[] $nums
+     * @return Integer
+     */
+    function minSubArrayLen($target, $nums) {
+        if (count($nums) < 1) {
+            return 0;
+        }
+        $sum = 0;
+        $res = PHP_INT_MAX;
+        $left = 0;
+        for ($right = 0; $right < count($nums); $right++) {
+            $sum += $nums[$right];
+            while ($sum >= $target) {
+                $res = min($res, $right - $left + 1);
+                $sum -= $nums[$left];
+                $left++;
+            }
+        }
+        return $res == PHP_INT_MAX ? 0 : $res;
+    }
+}
+```
 
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 * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)