decision trees another way to translate the message is with the use of decision tree decision tree models sequence of decisions or choices in which selections are made in stages from among multiple alternatives at each stage the stages in the decision are represented as nodes while the branches indicate the decisions that can be made at each stage common use of the decision tree with which you should be familiar is the dreaded automated phone menu when the automated system answers your callit starts at the root of the tree and offers several choices from which you can choose after making your initial selectionyou are presented with submenu from which you must make second selectionand then possibly third selectionand so on the presentation of the menu options by the automated system are the stages in the decision and represented in the tree as nodes the menu choices from which you can select at each stage are indicated by branches from those nodes this same idea can be used to decode morse code sequence while each code sequence is uniquethey do not have unique prefixes for examplethe sequences for the letters and both begin with dot to distinguish between the twowe have to examine more of the sequence the second symbol in the sequence for is dashwhile the sequence for has dot it' not until the third component of the sequence that we can fully distinguish between the and the to confuse the situation even morethe letter is indicated by the two-symbol sequence of -)which is the sequence prefix for subset of the international morse code is shown herea --- --- -- ---to help decode sequencewe can build decision tree that models morse codeas illustrated in figure the nodes represent the letters and symbols that are part of morse code and the branches provide selection of either dot (left branchor dash (right branchthe root node is empty and indicates the starting position when decoding sequence to decode given sequencewe start at the root and follow the left or right branch to the next node based on the current symbol in our sequence for exampleto decode )we start at the root and examine the first symbol since the first symbol is dotwe have to follow the left branch to the next nodewhich leads us to node each time we move to nodewe examine the next character in the sequence since the second symbol is dashwe take the right branch from node leading us to node from that nodewe take the left branch since the third symbol is dot this leads us to node after exhausting all of the symbols in the sequencethe last node visited will contain the character corresponding to the