Added solution to:
A tree, (NOT NECESSARILY BINARY), has nodes numbered 0 to N-1. An array has indices ranging from 0 to N-1. The indices denote the node ids and values denote the ids of parents. A value of -1 at some index k denotes that node with id k is the root. For ex:


3 3 3 -1 2
0 1 2 3 4
In the above, nodes with ids 0, 1 & 2 have 3 as parent. 3 is the root as its parent = -1 and 2 is the parent of node id 4.

Given such an array, find the height of the tree.