Update README.md

Author: yanglbme

solution/0000-0099/0002.Add Two Numbers/README.md

@@ -499,48 +499,44 @@ proc addTwoNumbers(l1: var SinglyLinkedList, l2: var SinglyLinkedList): SinglyLi
 ```c
 
 /**
-* Definition for singly-linked list.
-* struct ListNode {
-*     int val;
-*     struct ListNode *next;
-* };
-*/
-
-struct ListNode *addTwoNumbers(struct ListNode *l1, struct ListNode *l2)
-{
-   struct ListNode *dummy = (struct ListNode *)malloc(sizeof(struct ListNode));
-   dummy->val = 0;
-   dummy->next = NULL;
-   struct ListNode *curr = dummy;
-   int carry = 0;
-
-   while (l1 != NULL || l2 != NULL || carry != 0)
-   {
-       int sum = carry;
-       if (l1 != NULL)
-       {
-           sum += l1->val;
-           l1 = l1->next;
-       }
-       if (l2 != NULL)
-       {
-           sum += l2->val;
-           l2 = l2->next;
-       }
-
-       carry = sum / 10;
-       int val = sum % 10;
-
-       struct ListNode *newNode = (struct ListNode *)malloc(sizeof(struct ListNode));
-       newNode->val = val;
-       newNode->next = NULL;
-       curr->next = newNode;
-       curr = curr->next;
-   }
-
-   struct ListNode *result = dummy->next;
-   free(dummy);
-   return result;
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     struct ListNode *next;
+ * };
+ */
+
+struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2) {
+    struct ListNode* dummy = (struct ListNode*) malloc(sizeof(struct ListNode));
+    dummy->val = 0;
+    dummy->next = NULL;
+    struct ListNode* curr = dummy;
+    int carry = 0;
+
+    while (l1 != NULL || l2 != NULL || carry != 0) {
+        int sum = carry;
+        if (l1 != NULL) {
+            sum += l1->val;
+            l1 = l1->next;
+        }
+        if (l2 != NULL) {
+            sum += l2->val;
+            l2 = l2->next;
+        }
+
+        carry = sum / 10;
+        int val = sum % 10;
+
+        struct ListNode* newNode = (struct ListNode*) malloc(sizeof(struct ListNode));
+        newNode->val = val;
+        newNode->next = NULL;
+        curr->next = newNode;
+        curr = curr->next;
+    }
+
+    struct ListNode* result = dummy->next;
+    free(dummy);
+    return result;
 }
 ```