membership structures fig after inserting cowcatratrabbitand dog into trie tries are appropriate when key values are made up of more than one unit and when the individual units of key may overlap with other item keys in factthe more overlap the key units havethe more compact the trie data structure in the problem of spell checkingwords are made up of characters these characters are the individual units of the keys many words overlap in dictionary like aanand ant trie may be implemented in several different ways in this text we'll concentrate on the linked trie which is series of link lists making up matrix matrix implementations lead to sparsely populated arrays which take up much more room with empty locations linked trie has overhead for pointersbut is not sparsely populated the trie data structure begins with an empty linked list each node in the linked trie list contains three valuesa unit of the key (in the spellchecker instance this is character of the word) next pointer that points to the next node in the list which would contain some other unit ( characterappearing at the same position within key ( word)and follows pointer which points at node that contains the next unit within the same key in fig the follows pointer is in yellow while the next pointer field is in red this copy belongs to 'acha