In-place List Reversal
LC #25Hard
Reverse Nodes in k-Group
In-place List Reversal
GoogleAmazonMetaMicrosoftProblem
Reverse the nodes of a linked list k at a time. If remaining nodes are fewer than k, leave them as is.
linked-listrecursion
Constraints
- ›1 ≤ n ≤ 5000
- ›0 ≤ Node.val ≤ 1000
- ›1 ≤ k ≤ n
- ›If remaining nodes < k, leave them as-is
Example
Input
head = [1, 2, 3, 4, 5], k = 2Output
[2, 1, 4, 3, 5]Why
Groups: [1,2] → [2,1], [3,4] → [4,3], [5] left as-is (< k nodes)