Partition by a threshold in Java
Java interview exercise on Streams & lambdas, difficulty 2 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Write partition(nums, threshold) that returns a Map<Boolean, List<Integer>> with the numbers at or above the threshold under true and the rest under false, in their original order. Collectors.partitioningBy always produces both keys, even when one list is empty.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.