Airbnb Mobile Engineer Coding Questions

Airbnb app users require efficient battery management to prolong device usage while navigating to their destinations. Optimizing battery usage according to user preferences during their commute is essential.
Use dynamic programming to determine the minimal battery usage when users must traverse a series of n locations with associated batteryCosts that represent the battery consumption to move from one location to the next.
Function signature:
- int minBatteryUsage(int[] batteryCosts):
- Returns the minimum battery usage to navigate through all locations.Example 1:
Input: batteryCosts = [5, 10, 3, 8]
Output: 18
Explanation: In this case, the minimum battery usage is calculated as the sum of the smallest transitions: 5 + 3 + 10 = 18.
Constraints:
- batteryCosts.length <= 10^5
- batteryCosts[i] within [1, 100].

Airbnb handles several user location streams simultaneously to provide accurate search results based on proximity. Merging these streams efficiently is crucial for performance.
Given an array of locationStreams representing UserLocation objects containing longitude, latitude, and timestamp, merge these streams into one sorted array based on timestamp.
UserLocation class:
- class UserLocation:
- float longitude: longitude of the user.
- float latitude: latitude of the user.
- int timestamp: the timestamp when the location was recorded.Example 1:
Input: locations = [[UserLocation(-73.9857, 40.7484, 3), UserLocation(-73.9860, 40.7488, 2)], [UserLocation(-73.9856, 40.7481, 4)]]
Output: [UserLocation(-73.9860, 40.7488, 2), UserLocation(-73.9857, 40.7484, 3), UserLocation(-73.9856, 40.7481, 4)]
Explanation: The merged list is sorted by timestamp.
Constraints:
- locations.length <= 10^4
- locations[i].length <= 10^3
- longitude, latitude within [-180, 180].
- timestamp within [0, 10^9].