In an alternating permutation of numbers 1 to n, the numbers are arranged so that they alternately increase and decrease. For example, there are five alternating permutations of the numbers 1, 2, 3, and 4:
1 3 2 4
1 4 2 3
2 3 1 4
2 4 1 3
3 4 1 2
Write a function to count the alternating permutations for a set of n numbers.
Solution Stats
Problem Comments
3 Comments
Solution Comments
Show comments
Loading...
Problem Recent Solvers10
Suggested Problems
-
Back to basics 23 - Triangular matrix
1117 Solvers
-
Permute diagonal and antidiagonal
500 Solvers
-
Return a list sorted by number of consecutive occurrences
427 Solvers
-
How long do each of the stages of the rocket take to burn?
453 Solvers
-
121 Solvers
More from this Author321
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
The test case result for n=5 seems a tad high.
Tim, that last case is altperm(altperm(5)). I did that to discourage lookup solutions.
Oops--my mistake.