141. Swap Nodes in Pairs
Challenge1000 ms256 MBSolved by 0%
Swap every two adjacent nodes and print the result.
So 1 2 3 4 becomes 2 1 4 3. If the list has an odd number of nodes, the last one stays
where it is.
Swap the NODES by relinking them, not the values inside them.
Print Empty for an empty list.
Constraints - `0 ≤ n ≤ 100000` - `-1000000 ≤ value ≤ 1000000`
Input
The first line contains an integer n, the number of nodes.
The second line contains n space-separated integers, the node values from head to tail.
The starter code builds the list for you; work on the nodes, not the array.
Output
Print the resulting list from head to tail on ONE line, separated by single spaces, or Empty if no nodes remain.
Input4
1 2 3 4
Output2 1 4 3
Notehas an even length so every node moves
Input5
1 2 3 4 5
Output2 1 4 3 5
Notehas an odd length, so the last node stays put
Hints
Four rungs, in order. The last two open once you have submitted an attempt. A wrong one counts.
Hint 1Where to start
Hint 2The approachOpen hint 1 first. This one carries on from it.
Hint 3PseudocodeOpen hint 2 first. This one carries on from it.
Hint 4Full solutionOpen hint 3 first. This one carries on from it.