Update 2._Add_two_numbers.cpp

Leetcode/2._Add_two_numbers.cpp

@@ -1,18 +1,50 @@
-// 2. Add Two Numbers Solution
+// Add Two Numbers LeetCode Solution
+
+#include <iostream>
+
+struct ListNode {
+    int val;
+    ListNode *next;
+    ListNode(int x) : val(x), next(nullptr) {}
+};
+
 class Solution {
 public:
     ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
         ListNode *preHead = new ListNode(0), *p = preHead;
-    int extra = 0;
-    while (l1 || l2 || extra) {
-        int sum = (l1 ? l1->val : 0) + (l2 ? l2->val : 0) + extra;
-        extra = sum / 10;
-        p->next = new ListNode(sum % 10);
-        p = p->next;
-        l1 = l1 ? l1->next : l1;
-        l2 = l2 ? l2->next : l2;
+        int carry = 0;  // Carry from sum
+
+        while (l1 || l2 || carry) {
+            int sum = (l1 ? l1->val : 0) + (l2 ? l2->val : 0) + carry;
+            carry = sum / 10;  // Calculate the carry
+            p->next = new ListNode(sum % 10);  // Add the new node to the result list
+            p = p->next;  // Move the pointer to the next node
+            l1 = l1 ? l1->next : l1;
+            l2 = l2 ? l2->next : l2;
+        }
+
+        return preHead->next;  // Return the result list
     }
-    return preHead->next;
+};
+
+int main() {
+    // Usage example
+    Solution solution;
+    ListNode* l1 = new ListNode(2);
+    l1->next = new ListNode(4);
+    l1->next->next = new ListNode(3);
+
+    ListNode* l2 = new ListNode(5);
+    l2->next = new ListNode(6);
+    l2->next->next = new ListNode(4);
 
+    ListNode* result = solution.addTwoNumbers(l1, l2);
+
+    // Print the result
+    while (result) {
+        std::cout << result->val << " ";
+        result = result->next;
     }
-};
+
+    return 0;
+}