You can choose from in-person surveys (one-on-one interviews carried out at high-traffic locations), telephone surveys (less expensive than one-to-one interviews), mail surveys (easy to reach a large audience) and online surveys (simple and inexpensive way to collect data, though not reliable).
A binary tree of depth d is an almost complete binary tree if: 1  Each leaf in the tree is either at level d or at level d â 1. 2  For any node nd in the tree with a right descendant at level d, all the left descendants of nd that are leaves are also at level d.
A binary search tree (BST) is a binary tree where each node has a Comparable key (and an associated value) and satisfies the restriction that the key in any node is larger than the keys in all nodes in that node's left subtree and smaller than the keys in all nodes in that node's right subtree.