Nedbank Mock: Optimizing Resource Allocation (Q70)

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Problem

Given array arr of size n and integer k, find the maximum sum subarray of exactly length k where all elements are distinct. Return -1 if none exists.

Source

Nedbank VAS HackerRank Assessment - Q70
Tags: Easy, Greedy, Sliding Window, Arrays

References

• Related pattern: Pattern: Sliding Window (Arrays) #10

Constraints

• 1 <= k <= n <= 2 * 10^5
• 1 <= arr[i] <= 10^9

Example

n=6, k=3, arr=[1,2,3,7,3,5]
Output: 15  // [7,3,5]

Approach Hints

• Fixed-size window of length k
• Which data structure tracks uniqueness and frequency within the window?
• What do you do when a duplicate enters the window?

Complexity Target

• Time: O(n)
• Space: O(k)

Notes

Language: Java