chen0040 / pyalgs

            child = 2 * k

            if child < self.N and less(self.keys[self.pq[child]], self.keys[self.pq[child+1]]):

                child = child+1

            if less(self.keys[self.pq[child]], self.keys[self.pq[k]]):

                exchange(self.pq, k, child)

                self.qp[self.pq[k]] = k

                self.qp[self.pq[child]] = child

                k = child

            else:

                break

    def is_empty(self):

        return self.N == 0

    def swim(self, k):

        while k > 1:

            parent = k / 2

            if less(self.keys[self.pq[k]], self.keys[self.pq[parent]]):

                exchange(self.pq, k, parent)

                self.qp[self.pq[k]] = k

                self.qp[self.pq[parent]] = parent

                k = parent

            else:

                break

    def get(self, index):

        return self.keys[index]