Find the target key K in the given binary search tree, return the node that contains the key if K is found, otherwise return null.

Assumptions

• There are no duplicate keys in the binary search tree

  public TreeNode search(TreeNode root, int key) {
    while (root != null) {
      if (root.key == key) {
        return root;
      } else if (root.key < key) {
        root = root.right;
      } else {
        root = root.left;
      }
    }
    return null;
  }