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 Solvers14
Suggested Problems
-
Getting the indices from a matrix
735 Solvers
-
Create matrix of replicated elements
402 Solvers
-
Implement a bubble sort technique and output the number of swaps required
402 Solvers
-
251 Solvers
-
Divide the Least Common Multiple by the Greatest Common Divisor of two numbers
54 Solvers
More from this Author329
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.