feat: add php solution to lc problem: No.1941 (#1029)

Author: Qiu-IT

solution/1900-1999/1941.Check if All Characters Have Equal Number of Occurrences/README.md

@@ -156,6 +156,24 @@ function areOccurrencesEqual(s: string): boolean {
 }
 ```
 
+### **PHP**
+
+```php
+class Solution {
+    /**
+     * @param String $s
+     * @return Boolean
+     */
+    function areOccurrencesEqual($s) {
+        for ($i = 0; $i < strlen($s); $i++) {
+            $hashtable[$s[$i]] += 1;
+        }
+        $rs = array_unique($hashtable);
+        return count($rs) === 1;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1900-1999/1941.Check if All Characters Have Equal Number of Occurrences/README_EN.md

@@ -140,6 +140,24 @@ function areOccurrencesEqual(s: string): boolean {
 }
 ```
 
+### **PHP**
+
+```php
+class Solution {
+    /**
+     * @param String $s
+     * @return Boolean
+     */
+    function areOccurrencesEqual($s) {
+        for ($i = 0; $i < strlen($s); $i++) {
+            $hashtable[$s[$i]] += 1;
+        }
+        $rs = array_unique($hashtable);
+        return count($rs) === 1;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1900-1999/1941.Check if All Characters Have Equal Number of Occurrences/Solution.php

@@ -0,0 +1,13 @@
+class Solution {
+    /**
+     * @param String $s
+     * @return Boolean
+     */
+    function areOccurrencesEqual($s) {
+        for ($i = 0; $i < strlen($s); $i++) {
+            $hashtable[$s[$i]] += 1;
+        }
+        $rs = array_unique($hashtable);
+        return count($rs) === 1;
+    }
+}