JuniorArray
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
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2 4 1 1 6 5Input
nums = [2,4,1,1,6,5]Output
3There are 3 hills and valleys: index 1 is a hill, indices 2 and 3 are the same valley, and index 4 is a hill.
Example 2
# # # # # # # # # # # # # # # # # # # # # # # # # # # 6 6 5 5 4 1
Input
nums = [6,6,5,5,4,1]Output
0No index has closest non-equal neighbors that are both smaller or both larger, so there are 0 hills and valleys.
Constraints
- 3 <= nums.length <= 100
- 1 <= nums[i] <= 100
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