Binary Heap Parent and Child Indices

Problem

Return the parent and child indices of a node in an array-based binary heap.

For a zero-based index i, the parent is (i - 1) // 2 (or -1 for the root), the left child is 2*i + 1, and the right child is 2*i + 2.

Return [parent, left, right].

Hint

Children of i live at 2*i + 1 and 2*i + 2; the parent is their inverse.

case 1

in: [0]

expected: [-1,1,2]

case 2

in: [1]

expected: [0,3,4]

case 3

in: [3]

expected: [1,7,8]

case 4

in: [6]

expected: [2,13,14]

Starter codePython

def heap_indices(i):
    # Your code here
    pass

4 test cases · run your code against them in the editor