Changing direction

Changing direction

Simple+

You are given a sequence of integers. Your task in this mission is to find, how many times the sorting direction was changed in the given sequence. If the elements are equal - the previous sorting direction remains the same, if the sequence starts from the same elements - look for the next different to determine the sorting direction.

Let's look at the scheme:

changing_dir

There are three sorting directions:

  • on the chunk 1, 2, 2 - up (increasing);
  • on the chunk 2, 1 - down (decreasing);
  • and on the chunk 1, 2, 2 - up again.
So, you have two points of changing the sorting direction: #1 - from up to down, and #2 - from down to up. That's the result your function should return.

Input: Array of integers (number).

Output: An integer (number).

Examples: 

assert.strictEqual(changingDirection([1, 2, 3, 4, 5]), 0);
assert.strictEqual(changingDirection([1, 2, 3, 2, 1]), 1);
assert.strictEqual(changingDirection([1, 2, 2, 1, 2, 2]), 2);

Preconditions:

  • the sequence is non-empty;
  • the elements are positive integers.

17
freeman_lex
Solve as a guest
Sign in to your account