Count Hills and Valleys in an Array

You are given a 0-indexed integer array nums. An index i is part of a hill in nums if the closest non-equal neighbors of i are smaller than nums[i]. Similarly, an index i is part of a valley in nums if the closest non-equal neighbors of i are larger than nums[i]. Adjacent indices i and j are part of the same hill or valley if nums[i] == nums[j].

Note that for an index to be part of a hill or valley, it must have a non-equal neighbor on both the left and right of the index.

Return the number of hills and valleys in nums.

Example 1:

Input: nums = [2,4,1,1,6,5]
Output: 3
Explanation:
At index 0: There is no non-equal neighbor of 2 on the left, so index 0 is neither a hill nor a valley.
At index 1: The closest non-equal neighbors of 4 are 2 and 1. Since 4 > 2 and 4 > 1, index 1 is a hill. 
At index 2: The closest non-equal neighbors of 1 are 4 and 6. Since 1 < 4 and 1 < 6, index 2 is a valley.
At index 3: The closest non-equal neighbors of 1 are 4 and 6. Since 1 < 4 and 1 < 6, index 3 is a valley, but note that it is part of the same valley as index 2.
At index 4: The closest non-equal neighbors of 6 are 1 and 5. Since 6 > 1 and 6 > 5, index 4 is a hill.
At index 5: There is no non-equal neighbor of 5 on the right, so index 5 is neither a hill nor a valley. 
There are 3 hills and valleys so we return 3.

Example 2:

Input: nums = [6,6,5,5,4,1]
Output: 0
Explanation:
At index 0: There is no non-equal neighbor of 6 on the left, so index 0 is neither a hill nor a valley.
At index 1: There is no non-equal neighbor of 6 on the left, so index 1 is neither a hill nor a valley.
At index 2: The closest non-equal neighbors of 5 are 6 and 4. Since 5 < 6 and 5 > 4, index 2 is neither a hill nor a valley.
At index 3: The closest non-equal neighbors of 5 are 6 and 4. Since 5 < 6 and 5 > 4, index 3 is neither a hill nor a valley.
At index 4: The closest non-equal neighbors of 4 are 5 and 1. Since 4 < 5 and 4 > 1, index 4 is neither a hill nor a valley.
At index 5: There is no non-equal neighbor of 1 on the right, so index 5 is neither a hill nor a valley.
There are 0 hills and valleys so we return 0.

Constraints:

3 <= nums.length <= 100
1 <= nums[i] <= 100

Solution:

class Solution {

    /**
     * @param Integer[] $nums
     * @return Integer
     */
    function countHillValley($nums) {
        

        if( empty($nums) || count($nums) < 3 || count($nums) > 100 ) return 0;

        $counter = 0;

        for( $i = 1; $i < count($nums) - 1; $i++ ) {

            if($nums[$i] == $nums[$i-1] ) continue;

            $left = 0;
            $right = 0;
            for( $j = $i-1; $j >= 0 ; $j-- ) {
                if($nums[$j] != $nums[$i]) {
                    $left = $nums[$j];
                    break;
                }
            }

            if( $left == 0 ) continue;

            for( $j = $i+1; $j < count($nums) ; $j++ ) {
                if($nums[$j] != $nums[$i]) {
                    $right = $nums[$j];
                    break;
                }
            }
    
            if( $right == 0 ) continue;

            if( ($nums[$i] > $left && $nums[$i] > $right) || ( $nums[$i] < $left && $nums[$i] < $right ) ) {
                $counter++;
            }
        }   
        return $counter;
    }
}