leetcode

commit 1e6a5a481a66d788a6afb603324e805301aed129
parent ef88eba3d2a3e81f612772dfdd0cd13cd61f3d53
Author: Dimitrije Dobrota <mail@dimitrijedobrota.com>
Date:   Tue,  7 May 2024 13:30:40 +0200

Daily Problem

Diffstat:
A
Problems/2816.cpp
 | 
29
+++++++++++++++++++++++++++++
M
README.md
 | 
1
+

2 files changed, 30 insertions(+), 0 deletions(-)
diff --git a/Problems/2816.cpp b/Problems/2816.cpp
@@ -0,0 +1,29 @@
+class Solution {
+    static ListNode *rev(ListNode *list) {
+        ListNode *prev = nullptr, *next;
+        while (list) {
+            next = list->next;
+            list->next = prev;
+            prev = list;
+            list = next;
+        }
+        return prev;
+    }
+
+  public:
+    ListNode *doubleIt(ListNode *head) const {
+        head = rev(head);
+
+        ListNode *l = nullptr;
+        int carry = 0;
+        for (ListNode *p = head; p; l = p, p = p->next) {
+            const int val = p->val * 2 + carry;
+            p->val = val % 10;
+            carry = val / 10;
+        }
+
+        if (carry) l->next = new ListNode(carry);
+
+        return rev(head);
+    }
+};
diff --git a/README.md b/README.md
@@ -1189,6 +1189,7 @@ for solving problems.
 |  2785  |   Medium   | [Sort Vowels in a String](Problems/2785.cpp)                                                       |
 |  2799  |   Medium   | [Count Complete Subarrays in an Array](Problems/2799.cpp)                                          |
 |  2807  |   Medium   | [Insert Greatest Common Divisors in Linked List](Problems/2807.cpp)                                |
+|  2816  |   Medium   | [Double a Number Represented as a Linked List](Problems/2816.cpp)                                  |
 |  2840  |   Medium   | [Check if Strings Can be Made Equal With Operations II](Problems/2840.cpp)                         |
 |  2849  |   Medium   | [Determine if a Cell Is Reachable at a Given Time](Problems/2849.cpp)                              |
 |  2856  |   Medium   | [Minimum Array Length After Pair Removals](Problems/2856.cpp)                                      |