Grokking Data Structures & Algorithms for Coding Interviews
Ask Author
Back to course home

0% completed

Vote For New Content
Problem 5: Swap Nodes in Pairs (medium)
Table of Contents

Contents are not accessible

Contents are not accessible

Contents are not accessible

Contents are not accessible

Contents are not accessible

Problem Statement

Given a singly linked list, swap every two adjacent nodes and return the head of the modified list.

If the total number of nodes in the list is odd, the last node remains in place. Every node in the linked list contains a single integer value.

Examples

  1. Input: [1, 2, 3, 4]
    Output: [2, 1, 4, 3]
    Justification: Pairs (1,2) and (3,4) are swapped.

  2. Input: [7, 8, 9, 10, 11]
    Output: [8, 7, 10, 9, 11]
    Justification: Pairs (7,8) and (9,10) are swapped. 11 remains in its place as it has no adjacent node to swap with.

  3. Input: [5, 6]
    Output: [6, 5]
    Justification: The pair (5,6) is swapped.

Constraints:

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

Try it yourself

Try solving this question here:

Python3
Python3
. . . .

.....

.....

.....

Like the course? Get enrolled and start learning!

Table of Contents

Contents are not accessible

Contents are not accessible

Contents are not accessible

Contents are not accessible

Contents are not accessible