pq-heaps-ts/dist/max-heap.js

implementation of priority queues using heaps

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.MaxHeap = void 0;
// implement max heap for generic type
class MaxHeap {
    constructor() {
        this.heap = [];
        this.push = (num) => {
            this.heap.push(num);
            this.heapifyUp(this.heap.length - 1);
        };
        this.pop = () => {
            const max = this.heap[0];
            this.heap[0] = this.heap[this.heap.length - 1];
            this.heap.pop();
            this.heapifyDown(0);
            return max;
        };
        this.top = () => this.heap[0];
        this.heapifyUp = (index) => {
            if (index === 0)
                return;
            const parentIndex = Math.floor((index - 1) / 2);
            if (this.heap[index] > this.heap[parentIndex]) {
                [this.heap[index], this.heap[parentIndex]] = [
                    this.heap[parentIndex],
                    this.heap[index],
                ];
                this.heapifyUp(parentIndex);
            }
        };
        this.heapifyDown = (index) => {
            const leftChildIndex = index * 2 + 1;
            const rightChildIndex = index * 2 + 2;
            const leftChild = this.heap[leftChildIndex];
            const rightChild = this.heap[rightChildIndex];
            const largestChildIndex = leftChildIndex < this.heap.length && leftChild > rightChild
                ? leftChildIndex
                : rightChildIndex;
            if (this.heap[index] < this.heap[largestChildIndex]) {
                [this.heap[index], this.heap[largestChildIndex]] = [
                    this.heap[largestChildIndex],
                    this.heap[index],
                ];
                this.heapifyDown(largestChildIndex);
            }
        };
        this.size = () => this.heap.length;
        this.isEmpty = () => this.heap.length === 0;
        this.print = () => console.log(this.heap);
    }
}
exports.MaxHeap = MaxHeap;