Reverse Linked List II | Problems

Reverse the nodes of a linked list from position left to right.

Example: head = [1,2,3,4,5], left=2, right=4 → [1,4,3,2,5]

Sample Input

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Sample Output

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Constraints

1 <= n <= 500
-500 <= Node.val <= 500
1 <= left <= right <= n

Topics

Linked List

In-Place Reversal

function reverseBetween(head, left, right) {
  const dummy = {next: head};
  let prev = dummy;
  for (let i = 0; i < left - 1; i++) prev = prev.next;
  let curr = prev.next;
  for (let i = 0; i < right - left; i++) {
    const next = curr.next;
    curr.next = next.next;
    next.next = prev.next;
    prev.next = next;
  }
  return dummy.next;
}

Time: O(n) | Space: O(1)

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