Consider a node R of a complete binary tree whose value is stored in position i of an array representation for the tree. If R has a left child, where will the left child's position be in the array?

2*i+1
  • i+1
  • i+2
  • 2*i+2
  • \lfloor (i-1)/2 \rfloor

If you have a right sibling, it is at i+1.

If you have a left sibling, it is at i-1.

If you have a parent, it is at \lfloor (i-1)/2 \rfloor.

If you have a right child, it is at 2*i+2.

If you have a left child, it is at 2*i+1.