Update palindrome-number.cpp

Author: kamyu104

C++/palindrome-number.cpp

@@ -10,11 +10,21 @@ class Solution {
         int temp = x;
         int reversed = 0;
         while (temp != 0) {
+            if (isOverflow(reversed, temp % 10)) {
+                return false;
+            }
             reversed = reversed * 10 + temp % 10;
             temp = temp / 10;
         }
         return reversed == x;
     }
+
+private:
+    bool isOverflow(int q, int r) {
+        static const int max_q = numeric_limits<int>::max() / 10;
+        static const int max_r = numeric_limits<int>::max() % 10;
+        return (q > max_q) || (q == max_q && r > max_r);
+    }
 };
 
 // Time:  O(logx) = O(1)