Given the root of a binary tree, the value of a target node target, and an integer k, return an array of the values of all nodes that have a distance k from the target node.
You can return the answer in any order.
1 <= number of nodes <= 5000 <= Node.val <= 500Node.val are uniquetarget is the value of one of the nodes in the tree0 <= k <= 1000root = [3,5,1,6,2,0,8,null,null,7,4], target = 5, k = 2[7,4,1]root = [1], target = 1, k = 3[]