Reverse Nodes in k-Group
HardP2Coding
Given the head of a singly linked list and an integer k, reverse the nodes of the list k at a time and return the head. Only full groups of k nodes are reversed; if fewer than k nodes remain at the end, leave them as they are. Change the pointers; do not just swap values. A list node has val and next. The ListNode class is already defined for you.
Example 1
- Input
- head = [1,2,3,4,5], k = 2
- Output
- [2,1,4,3,5]
Example 2
- Input
- head = [1,2,3,4,5], k = 3
- Output
- [3,2,1,4,5]
Example 3
- Input
- head = [1,2,3], k = 1
- Output
- [1,2,3]
Constraints
- 1 <= k <= number of nodes <= 5000
- 0 <= Node.val <= 1000
Hints
Give it a real attempt first. Run shows which examples fail.
Saved automatically
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