init

binheap.js

@@ -0,0 +1,60 @@
+class BinHeap {
+	constructor(cond = (p, c) => p < c) {
+		this.cond = cond
+		this.data = []
+	}
+
+	getTop() { return this.data[0] }
+	getParent(idx) { return idx / 2 | 0 }
+	getChildLeft(idx) { return 2 * idx }
+	getChildRight(idx) { return 2 * idx + 1 }
+
+	insert(val) {
+		this.up(this.data.push(val) - 1)
+	}
+
+	extract() {
+		let res = this.data[0]
+
+		if (this.data.length > 1) {
+			this.data[0] = this.data.pop()
+			this.down(0)
+		} else {
+			this.data = []
+		}
+
+		return res
+	}
+
+	up(idx) {
+		while (this.getParent(idx) != idx && !this.cond(this.data[this.getParent(idx)], this.data[idx])) {
+			let tmp = this.data[this.getParent(idx)]
+			this.data[this.getParent(idx)] = this.data[idx]
+			this.data[idx] = tmp
+			idx = this.getParent(idx)
+		}
+	}
+
+	down(idx) {
+		let largest = idx
+		let left = this.getChildLeft(idx)
+		let right = this.getChildRight(idx)
+
+		if (left < this.data.length && this.cond(this.data[left], this.data[largest])) {
+			largest = left
+		}
+
+		if (right < this.data.length && this.cond(this.data[right], this.data[largest])) {
+			largest = right
+		}
+
+		if (largest != idx) {
+			let tmp = this.data[largest]
+			this.data[largest] = this.data[idx]
+			this.data[idx] = tmp
+
+			this.down(largest)
+		}
+	}
+}
+