algorithm/javascript-algorithms
1
0
Fork 0
mirror of https://github.com/trekhleb/javascript-algorithms.git synced 2025-07-06 09:23:18 +08:00
Code Issues Packages Projects Releases Wiki Activity

Clean up Heaps.

Browse Source
This commit is contained in:
Oleksii Trekhleb
2018-08-30 08:25:38 +03:00
parent bc50fff2ee
commit 68af4fc165
1 changed files with 10 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
src/data-structures/heap/Heap.js
View File

@ -47,7 +47,7 @@ export default class Heap {
* @return {boolean} * @return {boolean}
*/ */
hasParent(childIndex) { hasParent(childIndex) {
return childIndex > 0; return this.getParentIndex(childIndex) >= 0;
} }
/** /**
@ -144,17 +144,17 @@ export default class Heap {
/** /**
* @param {*} item * @param {*} item
* @param {Comparator} [customComparator] * @param {Comparator} [comparator]
* @return {Heap} * @return {Heap}
*/ */
remove(item, customComparator = this.compare) { remove(item, comparator = this.compare) {
// Find number of items to remove. // Find number of items to remove.
const numberOfItemsToRemove = this.find(item, customComparator).length; const numberOfItemsToRemove = this.find(item, comparator).length;
for (let iteration = 0; iteration < numberOfItemsToRemove; iteration += 1) { for (let iteration = 0; iteration < numberOfItemsToRemove; iteration += 1) {
// We need to find item index to remove each time after removal since // We need to find item index to remove each time after removal since
// indices are being changed after each heapify process. // indices are being changed after each heapify process.
const indexToRemove = this.find(item, customComparator).pop(); const indexToRemove = this.find(item, comparator).pop();
// If we need to remove last child in the heap then just remove it. // If we need to remove last child in the heap then just remove it.
// There is no need to heapify the heap afterwards. // There is no need to heapify the heap afterwards.
@ -164,6 +164,7 @@ export default class Heap {
// Move last element in heap to the vacant (removed) position. // Move last element in heap to the vacant (removed) position.
this.heapContainer[indexToRemove] = this.heapContainer.pop(); this.heapContainer[indexToRemove] = this.heapContainer.pop();
// Get parent.
const parentItem = this.parent(indexToRemove); const parentItem = this.parent(indexToRemove);
// If there is no parent or parent is in correct order with the node // If there is no parent or parent is in correct order with the node
@ -171,7 +172,7 @@ export default class Heap {
if ( if (
this.hasLeftChild(indexToRemove) this.hasLeftChild(indexToRemove)
&& ( && (
parentItem == null !parentItem
|| this.pairIsInCorrectOrder(parentItem, this.heapContainer[indexToRemove]) || this.pairIsInCorrectOrder(parentItem, this.heapContainer[indexToRemove])
) )
) { ) {
@ -187,14 +188,14 @@ export default class Heap {
/** /**
* @param {*} item * @param {*} item
* @param {Comparator} [customComparator] * @param {Comparator} [comparator]
* @return {Number[]} * @return {Number[]}
*/ */
find(item, customComparator = this.compare) { find(item, comparator = this.compare) {
const foundItemIndices = []; const foundItemIndices = [];
for (let itemIndex = 0; itemIndex < this.heapContainer.length; itemIndex += 1) { for (let itemIndex = 0; itemIndex < this.heapContainer.length; itemIndex += 1) {
if (customComparator.equal(item, this.heapContainer[itemIndex])) { if (comparator.equal(item, this.heapContainer[itemIndex])) {
foundItemIndices.push(itemIndex); foundItemIndices.push(itemIndex);
} }
} }