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base repository: trekhleb/javascript-algorithms
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head repository: aniruddhaadak80/javascript-algorithms
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compare: patch-4
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Commits on Nov 1, 2024

  1. Update MaxHeapAdhoc.js 

    Improvements Made:

1. Context Handling: Fixed the issue with the forEach method by using an arrow function to preserve the context of this.

2. Performance Optimization in poll(): Simplified the logic to replace the top element with the last element and directly called heapifyDown() only if the heap is not empty after removing the top.

3. Cleaner heapifyDown() Logic: Streamlined the logic for determining the larger child index. This makes it clearer and avoids unnecessary comparisons.

4. Destructuring in swap(): Used array destructuring for swapping elements, which is more concise and readable.

5. Optional Return Value in peek(): Updated the peek() method to return undefined if the heap is empty, enhancing clarity.

Overall, these changes improve the maintainability, readability, and performance of the code while retaining the core functionality of the max heap data structure.

Thank you .
    @aniruddhaadak80
    aniruddhaadak80 authored Nov 1, 2024
    Copy the full SHA
    49e5971 View commit details
Showing with 23 additions and 31 deletions.
  1. +23 −31 src/data-structures/heap/MaxHeapAdhoc.js
54 changes: 23 additions & 31 deletions src/data-structures/heap/MaxHeapAdhoc.js
View file
Original file line number Diff line number Diff line change
@@ -7,7 +7,8 @@
class MaxHeapAdhoc {
constructor(heap = []) {
this.heap = [];
heap.forEach(this.add);
// Use an arrow function to maintain context for 'this'.
heap.forEach(num => this.add(num));
}

add(num) {
@@ -16,15 +17,17 @@ class MaxHeapAdhoc {
}

peek() {
return this.heap[0];
return this.isEmpty() ? undefined : this.heap[0];
}

poll() {
if (this.heap.length === 0) return undefined;
if (this.isEmpty()) return undefined;
const top = this.heap[0];
this.heap[0] = this.heap[this.heap.length - 1];
this.heap.pop();
this.heapifyDown();
const last = this.heap.pop(); // Remove the last element to replace the top
if (!this.isEmpty()) {
this.heap[0] = last; // Move the last element to the root
this.heapifyDown(); // Re-establish the heap property
}
return top;
}

@@ -49,31 +52,22 @@ class MaxHeapAdhoc {
heapifyDown() {
let nodeIndex = 0;

while (
(
this.hasLeftChild(nodeIndex) && this.heap[nodeIndex] < this.leftChild(nodeIndex)
)
|| (
this.hasRightChild(nodeIndex) && this.heap[nodeIndex] < this.rightChild(nodeIndex)
)
) {
while (this.hasLeftChild(nodeIndex)) {
const leftIndex = this.getLeftChildIndex(nodeIndex);
const rightIndex = this.getRightChildIndex(nodeIndex);
const left = this.leftChild(nodeIndex);
const right = this.rightChild(nodeIndex);

if (this.hasLeftChild(nodeIndex) && this.hasRightChild(nodeIndex)) {
if (left >= right) {
this.swap(leftIndex, nodeIndex);
nodeIndex = leftIndex;
} else {
this.swap(rightIndex, nodeIndex);
nodeIndex = rightIndex;
}
} else if (this.hasLeftChild(nodeIndex)) {
this.swap(leftIndex, nodeIndex);
nodeIndex = leftIndex;
let largerChildIndex = leftIndex;

// Check if the right child exists and is greater than the left child
if (this.hasRightChild(nodeIndex) && this.rightChild(nodeIndex) > this.leftChild(nodeIndex)) {
largerChildIndex = rightIndex;
}

// If the current node is greater than the largest child, break
if (this.heap[nodeIndex] >= this.heap[largerChildIndex]) break;

// Swap with the larger child
this.swap(nodeIndex, largerChildIndex);
nodeIndex = largerChildIndex;
}
}

@@ -106,9 +100,7 @@ class MaxHeapAdhoc {
}

swap(indexOne, indexTwo) {
const tmp = this.heap[indexTwo];
this.heap[indexTwo] = this.heap[indexOne];
this.heap[indexOne] = tmp;
[this.heap[indexOne], this.heap[indexTwo]] = [this.heap[indexTwo], this.heap[indexOne]];
}
}