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Clean up Heaps.

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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
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19
src/data-structures/heap/Heap.js
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@ -47,7 +47,7 @@ export default class Heap {
* @return {boolean}
*/
hasParent(childIndex) {
return childIndex > 0;
return this.getParentIndex(childIndex) >= 0;
}
/**
@ -144,17 +144,17 @@ export default class Heap {
/**
* @param {*} item
* @param {Comparator} [customComparator]
* @param {Comparator} [comparator]
* @return {Heap}
*/
remove(item, customComparator = this.compare) {
remove(item, comparator = this.compare) {
// 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) {
// We need to find item index to remove each time after removal since
// 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.
// 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.
this.heapContainer[indexToRemove] = this.heapContainer.pop();
// Get parent.
const parentItem = this.parent(indexToRemove);
// If there is no parent or parent is in correct order with the node
@ -171,7 +172,7 @@ export default class Heap {
if (
this.hasLeftChild(indexToRemove)
&& (
parentItem == null
!parentItem
|| this.pairIsInCorrectOrder(parentItem, this.heapContainer[indexToRemove])
)
) {
@ -187,14 +188,14 @@ export default class Heap {
/**
* @param {*} item
* @param {Comparator} [customComparator]
* @param {Comparator} [comparator]
* @return {Number[]}
*/
find(item, customComparator = this.compare) {
find(item, comparator = this.compare) {
const foundItemIndices = [];
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);
}
}