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.
We'll describe several radix search trees, starting with the simplest and working up. 1. Tries. A trie is a binary tree (or more generally, a k-ary tree where k is the radix) where the root represents the empty bit sequence and the two children of a node representing sequence x represent the extended sequences x0 and x1 (or generally x0, x1, ... x(k-1)).