trees fig the call tree for computing fib( how are expressions and trees relatedwhat is binary search treeunder what conditions is binary search tree usefulwhat is depth first search and how does it relate to trees and search problemswhat are the three types of tree traversals we can do on binary treeswhat is grammar and what can we do with grammarread on to discover trees and their uses in computer science abstract syntax trees and expressions trees have many applications in computer science they are used in many different types of algorithms for instanceevery python program you write is converted to treeat least for little whilebefore it is executed by the python interpreter internallya python program is converted to tree-like structure called an abstract syntax treeoften abbreviated astbefore it is executed we can build our own abstract syntax trees for expressions so we can see how tree might be evaluated and why we would want to evaluate tree in chap linked lists were presented as way of organizing list trees may be stored using similar kind of structure if node in tree has two childrenthen that node would have two links to its children as opposed to linked list which has one link to the next node in the sequence consider the expression ( we can construct an abstract syntax tree for this expression as shown in fig since the operation is the last operation performed when evaluating this functionthe node will be at the root of the tree it has two subtreesthe expression to the left of the and then to the right of the this copy belongs to 'acha