Coding: Sliding Window Function | Dataford Interview Questions

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Problem

Datadog Metrics processing can group sequential three-dimensional coordinate values into fixed-size windows. Given an ordered sequence of 3D points and a window size k, return the coordinate-wise sum for every contiguous window of exactly k points.

The first output represents points 0 through k - 1. Each following window moves one position right, so update the previous sum by subtracting the point that leaves and adding the point that enters.

Formal Specification

Implement sliding_coordinate_sums(points, k).

Input points: a list of points, where each point is a list of exactly three integers [x, y, z].
Input k: a positive integer window size.
Output: a list of lists, where each output point is [sum_x, sum_y, sum_z] for one contiguous window.
Return an empty list when k is greater than the number of points.

Constraints

0 <= points.length <= 10^5
Each point contains exactly three integers
1 <= k <= 10^5
-10^9 <= points[i][j] <= 10^9
Return windows in their original left-to-right order

Function Signature

def sliding_coordinate_sums(points, k):