feat: add php solution to lc problem: No.0013 (doocs#952)

Author: Qiu-IT

solution/0000-0099/0013.Roman to Integer/README.md

@@ -186,6 +186,28 @@ func romanToInt(s string) int {
 }
 ```
 
+### **PHP**
+
+```php
+class Solution {
+    /**
+     * @param String $s
+     * @return Integer
+     */
+    function romanToInt($s) {
+        $hashmap = array('I' => 1, 'V' => 5, 'X' => 10, 'L' => 50, 'C' => 100, 'D' => 500, 'M' => 1000);
+        $rs = 0;
+        for ($i = 0; $i < strlen($s); $i++) {
+            $left = $hashmap[$s[$i]];
+            $right = $hashmap[$s[$i + 1]];
+            if ($left >= $right) $rs += $left;
+            else $rs -= $left;
+        }
+        return $rs;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0000-0099/0013.Roman to Integer/README_EN.md

@@ -164,6 +164,28 @@ func romanToInt(s string) int {
 }
 ```
 
+### **PHP**
+
+```php
+class Solution {
+    /**
+     * @param String $s
+     * @return Integer
+     */
+    function romanToInt($s) {
+        $hashmap = array('I' => 1, 'V' => 5, 'X' => 10, 'L' => 50, 'C' => 100, 'D' => 500, 'M' => 1000);
+        $rs = 0;
+        for ($i = 0; $i < strlen($s); $i++) {
+            $left = $hashmap[$s[$i]];
+            $right = $hashmap[$s[$i + 1]];
+            if ($left >= $right) $rs += $left;
+            else $rs -= $left;
+        }
+        return $rs;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0000-0099/0013.Roman to Integer/Solution.php

@@ -0,0 +1,17 @@
+class Solution {
+    /**
+     * @param String $s
+     * @return Integer
+     */
+    function romanToInt($s) {
+        $hashmap = array('I' => 1, 'V' => 5, 'X' => 10, 'L' => 50, 'C' => 100, 'D' => 500, 'M' => 1000);
+        $rs = 0;
+        for ($i = 0; $i < strlen($s); $i++) {
+            $left = $hashmap[$s[$i]];
+            $right = $hashmap[$s[$i + 1]];
+            if ($left >= $right) $rs += $left;
+            else $rs -= $left;
+        }
+        return $rs;
+    }
+}