[Problem] To suppress increases in the size of a fully indexable dictionary while making it possible for a target bit stream to be subjected to two types of selection operation employing the fully indexable dictionary.;[Solution] An information processing device (100) is provided with a storage unit (10) which stores a data structure (11) used to represent a bit stream formed using a first value and a second value. The data structure (11) includes: first data specifying the positions on the bit stream of all or some succession segments including a succession of one or more of the first value or the second value; second data specifying, for some of the succession segments, the number of first values that have appeared on the bit stream from the beginning of the bit stream as far as the succession segment; and third data specifying, for some of the succession segments, the number of second values that have appeared on the bit stream from the beginning of the bit stream as far as the succession segment.
