A new realization of a space-efficient deque is presented. The data structure is constructed from three singly resizable arrays, each of which is a blockwise-allocated pile (a heap without the order property). The data structure is easily explainable provided that one knows the classical heap concept. All core deque operations are performed in O(1) time in the worst case. Also, general modifying operations are provided which run in O(√n) time if the structure contains n elements. Experiences with an implementation of the data structure shows that, compared to an existing library implementation, the constants for some of the operations are unfavourably high, whereas others show improved running times.

@report{KM2001bS,
  author = {Jyrki Katajainen and Bjarke Buur Mortensen},
  title = {Experiences with the design and implementation of space-efficient
    deques},
  type = {CPH STL Report},
  number = {2001-7},
  institution = {Department of Computer Science, University of Copenhagen},
  year = {2001},
  pagetotal = {47},
}