SkewHeap - a self-balancing min heap with O(log n) performance
const SkewHeap = require("skewheap");
const q = new SkewHeap((a, b) => {
if (a < b) return -1;
if (b < a) return 1;
return 0;
});
for (let i = 0; i < 100; ++i) {
q.put(i);
}
while (!q.is_empty) {
const item = q.take();
}
A skew heap is a min heap (a priority queue) for which all destructive
operations (put, take) are implemented in terms of a single function,
merge. Operations on a skew heap have an ammortized performance of O(log n)
(in fact, it is slightly better than that). A skew heap's most interesting
characteristic is the ability to quickly merge with another skew heap.
Accepts one parameter, a function taking two arguments, which it compares and returns 1, 0, or -1. Returning -1 or 0 signifies that the first parameter is less than or equal to the second and should be ordered ahead of the second parameter.
Returns the number of items in the queue.
Returns true if the queue has no items in it.
Puts one or more items into the queue. Accepts a variable number of arguments. All arguments must be comparable via the comparison function provided to the constructor.
heap.put(42)
heap.put(1, 2, 3, 4)
Returns the next item from the queue. If there are no items in the queue,
returns undefined.
Drains all items from the heap and returns them in an array.
Non-destructively merges another heap with this heap, returning a new heap containing all of the items in both heaps.
const new_heap = one_heap.merge(another_heap);
Destructively absorbs all of the items in another heap. After calling this method, the other heap will be empty.
one_heap.absorb(another_heap);
Jeff Ober sysread@fastmail.fm
Copyright 2018 Jeff Ober
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