LeetCode

Problems and solutions for LeetCode.

Priority Queue

Several problems require access to a priority queue; however, TypeScript itself does not have such a built-in data structure.

LeetCode

LeetCode provides support for heaps via datastructures-js/priority-queue at version 5.4.0. This is the library used, because this repository is for LeetCode submissions.

A couple of gotchas for version 5.4.0 that don't exist in later versions:

• LeetCode uses require style imports and not import. Practically that means MaxPriorityQueue and MinPriorityQueue do not accept parameterized types.
• Also, MaxPriorityQueue and MinPriorityQueue are exported as values. To get the type, do InstanceType<typeof MaxPriorityQueue>.
• Primitives are wrapped. That is, if you do heap.enqueue(1), then you should heap.dequeue().element to get 1 back.
• Objects are not wrapped. That is, if you do heap.enqueue(foo), then you should do heap.dequeue() to get foo back, if foo is an object.

CoderPad

CoderPad has no official support for priority queues.

CodeSignal

CodeSignal's official documentation does not claim support for priority queues. However, there is documentation suggesting that heap-js is available.

Other

There are a few other options.

• Insert into an array and sort it afterwards. See simple-heap.ts.
• Use binary search to insert into an array and do not sort. See bs-search-heap.ts.
• Roll your own heap during the interview. You beast.
• Give up.