feat: add php solution to lc problem: No.2068 (#991)

Author: Qiu-IT

solution/2000-2099/2068.Check Whether Two Strings are Almost Equivalent/README.md

@@ -140,6 +140,29 @@ func checkAlmostEquivalent(word1 string, word2 string) bool {
 }
 ```
 
+### **PHP**
+
+```php
+class Solution {
+    /**
+     * @param String $word1
+     * @param String $word2
+     * @return Boolean
+     */
+    function checkAlmostEquivalent($word1, $word2) {
+        for ($i = 0; $i < strlen($word1); $i++) {
+            $hashtable[$word1[$i]] += 1;
+            $hashtable[$word2[$i]] -= 1;
+        }
+        $keys = array_keys($hashtable);
+        for ($j = 0; $j < count($keys); $j++) {
+            if (abs($hashtable[$keys[$j]]) > 3) return false;
+        }
+        return true;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/2000-2099/2068.Check Whether Two Strings are Almost Equivalent/README_EN.md

@@ -131,6 +131,29 @@ func checkAlmostEquivalent(word1 string, word2 string) bool {
 }
 ```
 
+### **PHP**
+
+```php
+class Solution {
+    /**
+     * @param String $word1
+     * @param String $word2
+     * @return Boolean
+     */
+    function checkAlmostEquivalent($word1, $word2) {
+        for ($i = 0; $i < strlen($word1); $i++) {
+            $hashtable[$word1[$i]] += 1;
+            $hashtable[$word2[$i]] -= 1;
+        }
+        $keys = array_keys($hashtable);
+        for ($j = 0; $j < count($keys); $j++) {
+            if (abs($hashtable[$keys[$j]]) > 3) return false;
+        }
+        return true;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/2000-2099/2068.Check Whether Two Strings are Almost Equivalent/Solution.php

@@ -0,0 +1,18 @@
+class Solution {
+    /**
+     * @param String $word1
+     * @param String $word2
+     * @return Boolean
+     */
+    function checkAlmostEquivalent($word1, $word2) {
+        for ($i = 0; $i < strlen($word1); $i++) {
+            $hashtable[$word1[$i]] += 1;
+            $hashtable[$word2[$i]] -= 1;
+        }
+        $keys = array_keys($hashtable);
+        for ($j = 0; $j < count($keys); $j++) {
+            if (abs($hashtable[$keys[$j]]) > 3) return false;
+        }
+        return true;
+    }
+}