I am given a matrices each with 4 columns such that each element's value is between 1 to 4. Their is recurring pattern between first two digits while other two are random digits of a row. I need to find a pattern and then reduce it's number of elements. I am new to this topic . I don't need a complete solution just a little hint that how should I begin with the problem ? Which lossless algorithm will be good to begin with the problem or I am going completely in wrong direction?