// Tree definition for problem 3 type BST = | Empty | TreeNode of int * BST * BST let rec insert value tree = match tree with // if tree is empty, add node with no following nodes | Empty -> TreeNode(value, Empty, Empty) // if tree has existsing node and new node value is less than previous node // then insert it on the left side of the existing node | TreeNode(oldVal, node1, node2) when value < oldVal -> TreeNode(oldVal, insert value node1, node2) // will recursively go until right spot is found // if tree has existing node and new node value is greater than previous node // then insert it on the right side of the existing node | TreeNode(oldVal, node1, node2) when value > oldVal -> TreeNode(oldVal, node1, insert value node2) // will recursively go until right spot is found // when value = oldVal, no insertion will take place since it already exists in the tree | _ -> tree let rec contains value = function | Empty -> false | TreeNode(compareVal, node1, node2) -> if value = compareVal then true elif value < compareVal then contains value node1 else contains value node2 let rec count func = function | Empty -> 0 | TreeNode(value, node1, node2) -> (count func node1) + (count func node2) + (if (func value) then 1 else 0) let evenCount tree = let result = count (fun value -> value % 2 = 0) tree result //printfn "%A" result let bt1 = insert 10 Empty let bt2 = insert 5 bt1 let bt3 = insert 3 bt2 let bt4 = insert 17 bt3 let bt5 = insert 12 bt4 let answer = evenCount bt5