Swap Nodes in Pairs

Easy

linked-listrecursion

Swap every two adjacent nodes of the list and return the new head. Swap the nodes themselves, not just their values.

Input: one line of space-separated integers — the list values (may be empty). Output: the resulting list's values, space-separated.

Example 1

Input:

1 2 3 4

Output:

2 1 4 3

Example 2

Input:

Output:

Example 3

Input:

1 2 3

Output:

2 1 3

Run your code against the sample tests, or Submit to run the full suite.

Easy

linked-listrecursion

Swap every two adjacent nodes of the list and return the new head. Swap the nodes themselves, not just their values.

Input: one line of space-separated integers — the list values (may be empty). Output: the resulting list's values, space-separated.

Example 1

Input:

1 2 3 4

Output:

2 1 4 3

Example 2

Input:

Output:

Example 3

Input:

1 2 3

Output:

2 1 3

Run your code against the sample tests, or Submit to run the full suite.