add leetcode 9

leetcode/9.py

@@ -0,0 +1,9 @@
+# Given an integer, return true if x is a palindrome
+
+
+class Solution:
+    def isPalindrome(self, x: int) -> bool:
+        str_x = str(x)
+        inv_str_x = str_x[::-1]
+        int_inv_str_x = int(inv_str_x)
+        return x == int_inv_str_x