Practice Swap Nodes in Pairs
Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.
Problem Statement
Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list's nodes (i.e., only nodes themselves may be changed.)
Source: Swap Nodes in Pairs on LeetCode. Use the original task for its coding environment and submissions.
Examples
# Example 1
Input
head = [1,2,3,4]
Output
[2,1,4,3]
# Example 2
Input
head = []
Output
[]
# Example 3
Input
head = [1]
Output
[1]
# Example 4
Input
head = [1,2,3]
Output
[2,1,3]
Constraints
The number of nodes in the list is in the range [0, 100].
0 <= Node.val <= 100
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