Add Two Numbers

Author: ssfxz

2.cpp

@@ -0,0 +1,27 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
+        int carry = 0;
+        ListNode * head = new ListNode(0);
+        ListNode * curr = head;
+        while (l1 != NULL || l2 != NULL || carry) {
+            int l1_val = l1 == NULL ? 0 : l1 -> val;
+            int l2_val = l2 == NULL ? 0 : l2 -> val;
+            int val = l1_val + l2_val + carry;
+            curr -> next = new ListNode(val % 10);
+            carry = val / 10;
+            l1 = l1 == NULL ? NULL : l1 -> next;
+            l2 = l2 == NULL ? NULL : l2 -> next;
+            curr = curr -> next;
+        }
+        return head -> next;
+    }
+};