Swap List Nodes in pairs

Given a linked list, swap every two adjacent nodes and return its head.

For example,
Given 1->2->3->4, you should return the list as 2->1->4->3.

Your algorithm should use only constant space. You may not modify the values in the list, only nodes itself can be changed.

Interview Code Editor
  • Solution Approach
  • Complete Solution
7928 successful submissions.
Asked In:
  • Microsoft
Click here to jump start your coding interview preparation