Time: 62 ms (23.45%), Space: 71.4 MB (81.09%) - LeetHub

Author: ayushnagar123

2-add-two-numbers/2-add-two-numbers.cpp

@@ -0,0 +1,40 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode() : val(0), next(nullptr) {}
+ *     ListNode(int x) : val(x), next(nullptr) {}
+ *     ListNode(int x, ListNode *next) : val(x), next(next) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
+        ListNode* head = l1;
+        ListNode* ans = head;
+        int sum, a = 0, b = 0, remainder = 0;
+        while(l1 || l2 || remainder) {
+            a = 0, b = 0;
+            if(l1){
+                a = l1->val;
+                l1 = l1->next;
+            }
+            if(l2){
+                b = l2->val;
+                l2 = l2->next;
+            }
+            sum = a + b + remainder;
+            head->next = new ListNode(sum%10);
+            remainder = sum/10;
+            head = head->next;
+        }
+        ListNode* temp = ans;
+        ans = ans->next;
+        delete temp;
+        return ans;
+    }
+};
+
+// Runtime: 36 ms, faster than 40.34% of C++ online submissions for Add Two Numbers.
+// Memory Usage: 71.5 MB, less than 11.15% of C++ online submissions for Add Two Numbers.