binaryHeap.js

class MaxBinaryHeap {
    constructor() {
        this.values = [41, 39, 33, 18, 27, 12];
    }
    
    insert(val) {
        this.values.push(val);
        this.bubbleUp(val);
        return this.values;
    }

    bubbleUp(val) {
        let index = this.values.length - 1;
        while(index > 0) {
            let parentIdx = Math.floor((index - 1) / 2);
            let parent = this.values[parentIdx];
            if (val <= parent) break;
            this.values[parentIdx] = val;
            this.values[index] = parent;
            index = parentIdx;
        }
    }

    extractMax() {
        const max = this.values[0]
        const end = this.values.pop();
        if (this.values.length > 0) {
            this.values[0] = end;
            this.bubbleDown();
        }
        return max;
    }

    bubbleDown() {
        let idx = 0;
        const length = this.values.length;
        const element = this.values[0];
        while (true) {
            let leftChildIdx = 2 * idx + 1;
            let rightChildIdx = 2 * idx + 2;
            let leftChild, rightChild;
            let swap = null;

            if (leftChildIdx < length) {
                leftChild = this.values[leftChildIdx];
                if (leftChild > element) {
                    swap = leftChildIdx;
                }
            }

            if (rightChildIdx < length) {
                rightChild = this.values[rightChildIdx];
                if (
                    (swap === null && rightChild > element) || 
                    (swap !== null && rightChild > leftChild)
                ) {
                    swap = rightChildIdx;
                }
            }
            
            if (swap === null) break;

            this.values[idx] = this.values[swap];
            this.values[swap] = element;
            idx = swap;
        }  
    }
}

class Node {
    constructor(val, priority) {
        this.val = val;
        this.priority = priority;
    }
}

// Priority Queue
class MinBinaryHeap {
    constructor() {
        this.values = [];
    }
    
    enqueue(val, priority) {
        let newNode = new Node(val, priority)
        this.values.push(newNode);
        this.bubbleUp(newNode);
        return this.values;
    }

    bubbleUp(node) {
        let index = this.values.length - 1;
        while(index > 0) {
            let parentIdx = Math.floor((index - 1) / 2);
            let parent = this.values[parentIdx];
            if (node.priority >= parent.priority) break;
            this.values[parentIdx] = node;
            this.values[index] = parent;
            index = parentIdx;
        }
    }

    dequeue() {
        const min = this.values[0]
        const end = this.values.pop();
        if (this.values.length > 0) {
            this.values[0] = end;
            this.bubbleDown();
        }
        return min;
    }

    bubbleDown() {
        let idx = 0;
        const length = this.values.length;
        const element = this.values[0];
        while (true) {
            let leftChildIdx = 2 * idx + 1;
            let rightChildIdx = 2 * idx + 2;
            let leftChild, rightChild;
            let swap = null;

            if (leftChildIdx < length) {
                leftChild = this.values[leftChildIdx];
                if (leftChild.priority < element.priority) {
                    swap = leftChildIdx;
                }
            }

            if (rightChildIdx < length) {
                rightChild = this.values[rightChildIdx];
                if (
                    (swap === null && rightChild.priority < element.priority) || 
                    (swap !== null && rightChild.priority < leftChild.priority)
                ) {
                    swap = rightChildIdx;
                }
            }
            
            if (swap === null) break;

            this.values[idx] = this.values[swap];
            this.values[swap] = element;
            idx = swap;
        }  
    }
}