Problem Description
Given an array of integers nums and an integer k, an element nums[i] is considered good if it is strictly greater than the elements at indices i - k and i + k (if those indices exist). If neither of these indices exists, nums[i] is still considered good. Return the sum of all the good elements in the array.
Key Insights
- An element is considered good if it is greater than its neighbors at indices i - k and i + k.
- Boundary conditions need to be handled since the first k elements and the last k elements may not have both neighbors.
- The solution involves iterating through the array while checking the conditions for each element.
Space and Time Complexity
Time Complexity: O(n)
Space Complexity: O(1)
Solution
The approach involves iterating through the array nums. For each element, we check if it is greater than the elements located at indices i - k and i + k. If the indices are out of bounds, we consider the element as good. We maintain a sum of all good elements and return it at the end. This approach utilizes a single pass through the array, ensuring optimal time complexity.