Leetcode Problem 2210. Count Hills and Valleys in an Array

2210. Count Hills and Valleys in an Array

Leetcode Solutions

Two Pointers Approach

  • Initialize a result counter res to 0.
  • Initialize a pointer j to 0 to keep track of the last unique element.
  • Iterate through the array starting from index 1 to the second-to-last index.
  • For each element at index i, check if it forms a hill or a valley by comparing it with the last unique element nums[j] and the next element nums[i + 1].
  • If a hill or valley is found, increment the result counter res and update the last unique element pointer j to the current index i.
  • Continue iterating until all elements have been checked.
  • Return the result counter res.
UML Thumbnail

Filter Unique Elements and Check Neighbors

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