chore(commit): force

package.json

@@ -8,7 +8,9 @@
   },
   "license": "MIT",
   "main": "./src/index.js",
-  "exports": "./src/index.js",
+  "exports": {
+    ".": "./src/index.js"
+  },
   "scripts": {
     "test": "npx @kmamal/testing",
     "update-exports": "node ./scripts/update-exports.mjs"

src/index.js

@@ -0,0 +1,91 @@
+const {
+	getParent,
+	getLeft,
+	getRight,
+} = require('@kmamal/util/array/tree/binary')
+const { sub } = require('@kmamal/util/operators/arithmetic/sub')
+
+class Heap {
+	constructor (init = [], options = {}) {
+		this._array = Array.from(init, ([ prio, value ], index) => ({ prio, value, index }))
+		this._compare = options.compare || sub
+		this._heapify()
+	}
+
+	get size () { return this._array.length }
+
+	add (prio, value) {
+		const index = this._array.length
+		const entry = { prio, value, index }
+		this._array.push(entry)
+		this._bubbleUp(entry)
+		return entry
+	}
+
+	remove (entry) {
+		const last = this._array[this._array.length - 1]
+		this._swap(entry, last)
+		this._array.pop()
+		this._bubbleDown(last)
+		return entry
+	}
+
+	update (entry, prio) {
+		const oldPrio = entry.prio
+		entry.prio = prio
+		this._compare(prio, oldPrio) < 0
+			? this._bubbleUp(entry)
+			: this._bubbleDown(entry)
+	}
+
+	min () { return this._array[0] }
+	pop () {
+		return this._array.length !== 0
+			? this.remove(this._array[0])
+			: undefined
+	}
+
+	_bubbleUp (entry) {
+		for (;;) {
+			const parent = this._array[getParent(entry.index)]
+			if (!parent) { break }
+
+			if (this._compare(parent.prio, entry.prio) < 0) { break }
+
+			this._swap(entry, parent)
+		}
+	}
+
+	_bubbleDown (entry) {
+		for (;;) {
+			const { index } = entry
+			const leftChild = this._array[getLeft(index)]
+			if (!leftChild) { break }
+
+			const rightChild = this._array[getRight(index)]
+			const minChild = !rightChild || this._compare(leftChild.prio, rightChild.prio) <= 0 ? leftChild : rightChild
+			if (this._compare(entry.prio, minChild.prio) < 0) { break }
+
+			this._swap(entry, minChild)
+		}
+	}
+
+	_swap (a, b) {
+		const ai = a.index
+		const bi = b.index
+		this._array[bi] = a
+		this._array[ai] = b
+		a.index = bi
+		b.index = ai
+	}
+
+	_heapify () {
+		const first = getParent(this._array.length - 1)
+		for (let i = first; i >= 0; i--) {
+			const entry = this._array[i]
+			this._bubbleDown(entry)
+		}
+	}
+}
+
+module.exports = { Heap }

src/index.test.js

@@ -0,0 +1,16 @@
+const { test } = require('@kmamal/testing')
+const { Heap } = require('.')
+
+test("structs.Heap Heapsort", (t) => {
+	const a = [ 4, 7, 1, 3, 2, 9, 0, 5, 8, 6 ]
+	const expected = [ ...a ]
+	expected.sort()
+
+	const heap = new Heap(a.map((x) => [ x, x ]))
+	const result = []
+	while (heap.size) {
+		result.push(heap.pop().value)
+	}
+
+	t.equal(result, expected)
+})