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You are given a tree with n nodes numbered from 0 to n - 1 in the form of a parent array parent where parent[i] is the parent of ith node. The root of the tree is node 0. Find the kth ancestor of a given node.

The kth ancestor of a tree node is the kth node in the path from that node to the root node.

Implement the TreeAncestor class:

  • TreeAncestor(int n, int[] parent) Initializes the object with the number of nodes in the tree and the parent array.
  • int getKthAncestor(int node, int k) return the kth ancestor of the given node node. If there is no such ancestor, return -1.

 

Example 1:

Input
["TreeAncestor", "getKthAncestor", "getKthAncestor", "getKthAncestor"]
[[7, [-1, 0, 0, 1, 1, 2, 2]], [3, 1], [5, 2], [6, 3]]
Output
[null, 1, 0, -1]

Explanation
TreeAncestor treeAncestor = new TreeAncestor(7, [-1, 0, 0, 1, 1, 2, 2]);
treeAncestor.getKthAncestor(3, 1); // returns 1 which is the parent of 3
treeAncestor.getKthAncestor(5, 2); // returns 0 which is the grandparent of 5
treeAncestor.getKthAncestor(6, 3); // returns -1 because there is no such ancestor

 

Constraints:

  • 1 <= k <= n <= 5 * 104
  • parent.length == n
  • parent[0] == -1
  • 0 <= parent[i] < n for all 0 < i < n
  • 0 <= node < n
  • There will be at most 5 * 104 queries.

class TreeAncestor: def __init__(self, n: int, parent: List[int]): def getKthAncestor(self, node: int, k: int) -> int: # Your TreeAncestor object will be instantiated and called as such: # obj = TreeAncestor(n, parent) # param_1 = obj.getKthAncestor(node,k)