At most 1+2+4+8=15 vertices occur before level four. Level four can contain 16 vertices. Put t last on that full level to attain n=15+16=31. BFS cannot visit a deeper level first, so this is maximal.
More Trees and Binary Search Trees questions
GATE 2016 CS (CS2) Q46– New-order traversal visits root, then right subtree in New-order, then left subtree in…
GATE 2016 CS (CS2) Q50– How many insertion orders of 1,2,3,4,5,6,7 give a binary search tree of height six? A…
GATE 2017 CS (CS2) Q46– BST preorder is 12,8,6,2,7,9,10,16,15,19,17,20. Find its postorder.
GATE 2012 CS (CS1) Q57– Height counts edges on the longest downward path. Fill B1 and B2.
GATE 2013 CS (CS1) Q17– What is the tightest worst-case upper bound for inserting into a binary search tree with n…
GATE 2013 CS (CS1) Q53– A BST has preorder 30,20,10,15,25,23,39,35,42. Find its postorder.