Implicit data structure

In computer science, an implicit data structure stores very little information other than the main or required data. These storage schemes retain no pointers, represent a file of n k-key records as an n by k array. In implicit data structures, the only structural information is to allow the array to grow and shrink. It is called "implicit" because the order of the elements carries meaning. Another term used interchangeably is space efficient. Definitions of “very little” are vague and can mean from O(1) to O(log n) extra space. Everything is accessed in-place, by reading bits at various positions in the data. To achieve memory-optimal coding, appropriate data items use bits instead of bytes. Implicit data structures are also succinct data structures.