bioinformatics-python/heap.py at main · wavetearz/bioinformatics-python · GitHub

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class Heap:
    def __init__(self, t, size):
        self.heap = t
        self.size = size
        self.buildHeap()

    def leftChild(self, index):
        return 2 * index + 1

    def rightChild(self, index):
        return 2 * index + 2

    def parentIndex(self, index):
        return (index - 1) // 2

    def heapify(self, index):
        left = self.leftChild(index)
        right = self.rightChild(index)
        largest = index

        if (left < self.size) and (self.heap[left] > self.heap[largest]):
            largest = left
        if (right < self.size) and (self.heap[right] > self.heap[largest]):
            largest = right

        if largest != index:
            self.heap[index], self.heap[largest] = self.heap[largest], self.heap[index]
            self.heapify(largest)

    def buildHeap(self):
        for index in range((len(self.heap) // 2)-1, -1, -1): # idziemy od tylu
            self.heapify(index)

    def display(self):
        for value in self.heap[:self.size]:
            print(f"{value} ", end="")
        print("")

    def getMax(self):
        if self.size == 0:
            return None
        return self.heap[0]


    def extractMax(self):
        if self.size < 1:
            return None
        max = self.heap[0]
        self.heap[0] = self.heap[self.size - 1]
        self.size -= 1
        self.heapify(0)
        return max

    def increaseKey(self, index, newValue):
        self.heap[index] = newValue
        while index > 0 and (self.heap[self.parentIndex(index)] < newValue):
            parent = self.parentIndex(index)
            temp = self.heap[index]
            self.heap[index] = self.heap[parent]
            self.heap[parent] = temp
            index = parent


    def insert(self, value):
        self.size += 1
        if self.size > len(self.heap):
            self.heap.append(float('-inf')) # bardzo mala wartosc, zeby kolejnosc sie nie popsula
        else:
            self.heap[self.size - 1] = float('-inf')
        self.increaseKey(self.size - 1, value)


heap = Heap([4, 1, 3, 2, 16, 9, 10, 14, 8, 7], 10)

heap.display()
heap.insert(15)
heap.display()
print(heap.getMax())
heap.display()
print(heap.extractMax())
heap.display()
heap.increaseKey(4, 19)
heap.display()