Swift MinHeap

MinHeap.swift

class MinHeap {
	var harr:[Int] = Array<Int>()

	init() {

	}
	
	func getMin() -> Int {
		return harr[0]
	}

	func left(num:Int) -> Int {
		return num * 2 + 1;
	}

	func right(num:Int) -> Int {
		return num * 2 + 2;
	}

	func parent(num:Int) -> Int {
		return num == 0 ? -1 : (num-1)/2
	}

	func insert(num:Int) {
		harr.append(num)
		if (harr.count > 1){
			let index = harr.count - 1
			bubbleUp(index)
		}
		print(harr)
	}

	func removeMin() -> Int {
		print("Before removing Min: \(harr)")
		let currentMin = harr[0]
		let lastItem = harr.removeAtIndex(harr.count - 1)
		harr[0] = lastItem
		bubbleDown(0)
		print("After removing Min: \(harr)")
		return currentMin
	}

	func bubbleUp(index:Int) {
		var idx = index
		var parentItemIndex = parent(idx)
		while idx > 0 && harr[parentItemIndex] > harr[idx] {
			print("\(index) vs \(parentItemIndex)")

			let currentItem = harr[idx]
			let parentItem = harr[parentItemIndex]

			harr[idx] = parentItem
			harr[parentItemIndex] = currentItem

			print(parentItemIndex)

			idx = parentItemIndex
			parentItemIndex = parent(idx)
		}
	}
	
	func bubbleDown(index:Int) {
		var idx = index
		var minChildIdx = minChildIndex(idx)
		if minChildIdx != -1 && harr[minChildIdx] < harr[idx] {
			let currentItem = harr[idx]
			let childItem = harr[minChildIdx]
			
			harr[idx] = childItem
			harr[minChildIdx] = currentItem
			
			idx = minChildIdx
			minChildIdx = minChildIndex(idx)
		}
	}
	
	func minChildIndex(num:Int) -> Int {
		if left(num) > (harr.count - 1) { return -1 }
		if right(num) > (harr.count - 1) { return left(num) }
		return harr[left(num)] <= harr[right(num)] ? left(num) : right(num)
	}
}

var minHeap = MinHeap()
minHeap.insert(50)
minHeap.insert(20)
minHeap.insert(10)
minHeap.insert(7)

print("Remove Min")
print(minHeap.getMin())
minHeap.removeMin()
print(minHeap.getMin())
minHeap.removeMin()
print(minHeap.getMin())
minHeap.removeMin()
print(minHeap.getMin())