881. Inorder Successor in BST

Given the root of a binary search tree and a target value, return the in-order successor of the target — the smallest key strictly greater than the target. Return -1 if no successor exists. The target may or may not be present. The input gives a level-order BST array and the target separated by ' | '.

Input: A level-order BST array and the target, separated by ' | '.

Output: Integer — the successor value, or -1.

Examples

Input: [8,3,10,1,6,null,14] | 6
Output: 8
Explanation: Smallest key greater than 6.

Input: [8,3,10,1,6,null,14] | 14
Output: -1
Explanation: No successor for the maximum.

Input: [5] | 1
Output: 5
Explanation: 5 is the next greater key.

Constraints

• 0<=nodes<=10^4
• valid BST

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