Create double-a-number-represented-as-a-linked-list.cpp

Author: kamyu104

C++/double-a-number-represented-as-a-linked-list.cpp

@@ -0,0 +1,19 @@
+// Time:  O(n)
+// Space: O(1)
+
+// linked list
+class Solution {
+public:
+    ListNode* doubleIt(ListNode* head) {
+        if (head->val >= 5) {
+            head = new ListNode(0, head);
+        }
+        for (auto curr = head; curr; curr = curr->next) {
+            curr->val = (curr->val * 2) % 10;
+            if (curr->next && curr->next->val >= 5) {
+                ++curr->val;
+            }
+        }
+        return head;
+    }
+};