In LZ78 compression, this algorithm does compression by replacing repeated occurrences of data with references to a dictionary. The dictionary used for this algorithm is built based on the input data stream. The dictionary stores tuples that represent a set of characters that were part of the input data stream. Each index of a dictionary contains a tuple and its respective character. A tuple stored in an index of the dictionary contains a certain index of the dictionary and a character. Each dictionary item with its respective tuple will be represented as codice_1. Within this type of tuple, the index refers to a point in the dictionary where there is an occurrence of a duplicated part of the dictionary. 