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
-
Make the vector [1 2 3 4 5 6 7 8 9 10]
52973 Solvers
-
Make an awesome ramp for a tiny motorcycle stuntman
753 Solvers
-
Given a matrix, swap the 2nd & 3rd columns
1265 Solvers
-
Area of an equilateral triangle
6817 Solvers
-
352 Solvers
More from this Author323
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.