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zenglekiddzenglekidd
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Added data structure playground
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‎0. Data Structures.playground/Contents.swift‎

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import Foundation
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//struct MinHeap {
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// var items: [Int] = []
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//
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// //Get Index
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// private func getLeftChildIndex(_ parentIndex: Int) -> Int {
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// return 2 * parentIndex + 1
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// }
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// private func getRightChildIndex(_ parentIndex: Int) -> Int {
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// return 2 * parentIndex + 2
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// }
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// private func getParentIndex(_ childIndex: Int) -> Int {
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// return (childIndex - 1) / 2
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// }
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//
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// // Boolean Check
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// private func hasLeftChild(_ index: Int) -> Bool {
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// return getLeftChildIndex(index) < items.count
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// }
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// private func hasRightChild(_ index: Int) -> Bool {
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// return getRightChildIndex(index) < items.count
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// }
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// private func hasParent(_ index: Int) -> Bool {
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// return getParentIndex(index) >= 0
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// }
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//
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// // Return Item From Heap
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// private func leftChild(_ index: Int) -> Int {
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// return items[getLeftChildIndex(index)]
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// }
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// private func rightChild(_ index: Int) -> Int {
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// return items[getRightChildIndex(index)]
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// }
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// private func parent(_ index: Int) -> Int {
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// return items[getParentIndex(index)]
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// }
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//
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// // Heap Operations
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// mutating private func swap(indexOne: Int, indexTwo: Int) {
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// let placeholder = items[indexOne]
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// items[indexOne] = items[indexTwo]
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// items[indexTwo] = placeholder
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// }
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//
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// public func peek() -> Int {
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// if items.count != 0 {
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// return items[0]
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// } else {
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// fatalError()
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// }
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// }
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//
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// mutating public func poll() -> Int {
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// if items.count != 0 {
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// let item = items[0]
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// items[0] = items[items.count - 1]
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// heapifyDown()
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// items.removeLast()
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// return item
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// } else {
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// fatalError()
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// }
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// }
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//
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// mutating public func add(_ item: Int) {
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// items.append(item)
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// heapifyUp()
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// }
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//
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// mutating private func heapifyUp() {
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// var index = items.count - 1
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// while hasParent(index) && parent(index) > items[index] {
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// swap(indexOne: getParentIndex(index), indexTwo: index)
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// index = getParentIndex(index)
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// }
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// }
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//
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// mutating private func heapifyDown() {
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// var index = 0
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// while hasLeftChild(index) {
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// var smallerChildIndex = getLeftChildIndex(index)
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// if hasRightChild(index) && rightChild(index) < leftChild(index) {
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// smallerChildIndex = getRightChildIndex(index)
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// }
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//
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// if items[index] < items[smallerChildIndex] {
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// break
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// } else {
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// swap(indexOne: index, indexTwo: smallerChildIndex)
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// }
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// index = smallerChildIndex
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// }
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// }
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//}
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struct MaxHeap<Element: Comparable> {
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var items: [Element] = []
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public mutating func add(_ item: Element) {
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items.append(item)
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heapifyUp()
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}
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public mutating func poll() -> Element? {
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if isEmpty() {return nil}
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let result = items.first!
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items[0] = items.last!
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heapifyDown()
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items.removeLast()
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return result
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}
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public func peek() -> Element? {
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if isEmpty() {return nil}
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return items.first!
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}
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public func isEmpty() -> Bool {
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return items.count == 0
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}
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private mutating func heapifyUp() {
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if isEmpty() {return}
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var index = items.count - 1
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while hasParent(index) && items[index] > items[parentIndex(index)] {
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swap(index, parentIndex(index))
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index = parentIndex(index)
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}
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}
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private mutating func heapifyDown() {
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if isEmpty() {return}
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var index = 0
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while hasLeftChild(index) {
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if hasRightChild(index) {
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if leftChild(index) > rightChild(index) {
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swap(index, leftChildIndex(index))
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index = leftChildIndex(index)
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continue
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} else {
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swap(index, rightChildIndex(index))
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index = rightChildIndex(index)
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continue
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}
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}
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swap(index, leftChildIndex(index))
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index = leftChildIndex(index)
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}
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}
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private func leftChild(_ index: Int) -> Element {
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return items[leftChildIndex(index)]
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}
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private func rightChild(_ index: Int) -> Element {
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return items[rightChildIndex(index)]
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}
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private func parent(_ index: Int) -> Element {
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return items[parentIndex(index)]
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}
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private func leftChildIndex(_ index: Int) -> Int {
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return 2 * index + 1
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}
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private func rightChildIndex(_ index: Int) -> Int {
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return 2 * index + 2
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}
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private func parentIndex(_ index: Int) -> Int {
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return (index - 1) / 2
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}
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private func hasLeftChild(_ index: Int) -> Bool {
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return leftChildIndex(index) < items.count
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}
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private func hasRightChild(_ index: Int) -> Bool {
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return rightChildIndex(index) < items.count
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}
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private func hasParent(_ index: Int) -> Bool {
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return parentIndex(index) >= 0
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}
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private mutating func swap(_ indexOfFirst: Int, _ indexOfSecond: Int) {
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let temp = items[indexOfFirst]
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items[indexOfFirst] = items[indexOfSecond]
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items[indexOfSecond] = temp
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}
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}
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var array = Array(0...10)
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var randomArray = array.shuffled()
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print(randomArray)
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var heap = MaxHeap<Int>()
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for i in randomArray {
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heap.add(i)
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}
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var result: [Int] = []
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while heap.items.count != 0 {
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result.append(heap.poll()!)
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}
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print(result)

‎0. Data Structures.playground/contents.xcplayground‎

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<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
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<playground version='5.0' target-platform='ios' buildActiveScheme='true'>
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<timeline fileName='timeline.xctimeline'/>
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</playground>

‎0. Data Structures.playground/playground.xcworkspace/contents.xcworkspacedata‎

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