Partition List

Partition List

Given the head of a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.

You should preserve the original relative order of the nodes in each of the two partitions.

Examples

Example 1:

Input: head = [1, 4, 3, 2, 5, 2], x = 3
Output: [1, 2, 2, 4, 3, 5]

Example 2:

Input: head = [2, 1], x = 2
Output: [1, 2]

Constraints

• The number of nodes in the list is in the range [0, 200].
• -100 <= Node.val <= 100
• -200 <= x <= 200

Expected Complexity

• Time: O(n)
• Space: O(1) (reusing existing nodes)