Create 2.AddTwoNumbers.cpp

Author: reza-ebrahimi

2.AddTwoNumbers.cpp

@@ -0,0 +1,51 @@
+///
+/// LeetCode 
+/// By Reza Ebrahimi <reza.ebrahimi.dev@gmail.com>
+///
+/// 2. Add Two Numbers
+/// https://leetcode.com/problems/add-two-numbers
+///
+/// Time Submitted | Status   | Runtime | Memory | Language
+/// 2020/03/11     | Accepted | 20 ms	| 11.1 MB| cpp
+///
+/// Runtime: 20 ms, faster than 98.04% of C++ online submissions for Add Two Numbers.
+/// Memory Usage: 11.1 MB, less than 5.14% of C++ online submissions for Add Two Numbers.
+///
+
+
+
+/*
+Definition for singly-linked list.
+struct ListNode {
+    int val;
+    ListNode *next;
+    ListNode(int x) : val(x), next(NULL) {}
+};
+*/
+
+#include <iostream>
+
+class Solution {
+public:
+    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
+        ListNode *main_node = new ListNode(0);
+        ListNode *node = main_node;
+        int carry = 0;
+        
+        while (l1 != nullptr || l2 != nullptr) {
+            int val1 = l1 != nullptr ? l1->val : 0;
+            int val2 = l2 != nullptr ? l2->val : 0;
+            
+            int sum = val1 + val2 + carry;
+            carry = sum / 10;
+            
+            node->next = new ListNode(sum % 10);
+            node = node->next;
+            
+            l1 = l1 != nullptr ? l1->next : nullptr;
+            l2 = l2 != nullptr ? l2->next : nullptr;         
+        }
+        node->next = carry ? new ListNode(carry) : nullptr;
+        return main_node->next;
+    }
+};