feat: add php solution to lc problem: No.1426 (doocs#1016)

Author: Qiu-IT

solution/1400-1499/1426.Counting Elements/README.md

@@ -213,6 +213,24 @@ var countElements = function (arr) {
 };
 ```
 
+### **PHP**
+
+```php
+class Solution {
+    /**
+     * @param Integer[] $arr
+     * @return Integer
+     */
+    function countElements($arr) {
+        $cnt = 0;
+        for ($i = 0; $i < count($arr); $i++) {
+            if (in_array($arr[$i] + 1, $arr)) $cnt++;
+        }
+        return $cnt++;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1400-1499/1426.Counting Elements/README_EN.md

@@ -190,6 +190,24 @@ var countElements = function (arr) {
 };
 ```
 
+### **PHP**
+
+```php
+class Solution {
+    /**
+     * @param Integer[] $arr
+     * @return Integer
+     */
+    function countElements($arr) {
+        $cnt = 0;
+        for ($i = 0; $i < count($arr); $i++) {
+            if (in_array($arr[$i] + 1, $arr)) $cnt++;
+        }
+        return $cnt++;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1400-1499/1426.Counting Elements/Solution.php

@@ -0,0 +1,13 @@
+class Solution {
+    /**
+     * @param Integer[] $arr
+     * @return Integer
+     */
+    function countElements($arr) {
+        $cnt = 0;
+        for ($i = 0; $i < count($arr); $i++) {
+            if (in_array($arr[$i] + 1, $arr)) $cnt++;
+        }
+        return $cnt++;
+    }
+}