yqueue/dist/binary-heap.js

Yet another concurrent task queue

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.BinaryHeap = void 0;
class BinaryHeap {
    constructor(compare) {
        this.compare = compare;
        this.values = [];
    }
    get length() {
        return this.values.length;
    }
    add(element) {
        this.values.push(element);
        let index = this.values.length - 1;
        const current = this.values[index];
        try {
            while (index > 0) {
                const parentIndex = Math.floor((index - 1) / 2);
                const parent = this.values[parentIndex];
                if (this.compare(parent, current) < 0) {
                    this.values[parentIndex] = current;
                    this.values[index] = parent;
                    index = parentIndex;
                }
                else
                    break;
            }
        }
        catch (e) {
            // compare function throws an error.
            this.values.pop();
            throw e;
        }
    }
    peek() {
        var _a;
        return (_a = this.values[0]) !== null && _a !== void 0 ? _a : null;
    }
    removeMax() {
        var _a;
        if (this.values.length <= 1)
            return (_a = this.values.pop()) !== null && _a !== void 0 ? _a : null;
        const max = this.values[0];
        const end = this.values[this.values.length - 1];
        this.values[0] = end;
        this.values.pop();
        let index = 0;
        const length = this.values.length;
        const current = this.values[0];
        for (;;) {
            const leftChildIndex = 2 * index + 1;
            const rightChildIndex = 2 * index + 2;
            let leftChild = null;
            let rightChild = null;
            let swap = null;
            if (leftChildIndex < length) {
                leftChild = this.values[leftChildIndex];
                if (this.compare(leftChild, current) > 0)
                    swap = leftChildIndex;
                if (rightChildIndex < length) {
                    rightChild = this.values[rightChildIndex];
                    if ((swap === null && this.compare(rightChild, current) > 0) ||
                        (swap !== null && this.compare(rightChild, leftChild) > 0)) {
                        swap = rightChildIndex;
                    }
                }
            }
            if (swap === null)
                break;
            this.values[index] = this.values[swap];
            this.values[swap] = current;
            index = swap;
        }
        return max;
    }
}
exports.BinaryHeap = BinaryHeap;
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