Ordered sequence: Difference between revisions

From Algowiki
Jump to navigation Jump to search
Line 5: Line 5:
'''Representation invariant:'''
'''Representation invariant:'''
# The abstract data structure '''ordered sequence''' implements sorted sequences as defined [[Sets and sequences|here]].
# The abstract data structure '''ordered sequence''' implements sorted sequences as defined [[Sets and sequences|here]].
# This abstract data structure is [[Genericity|generic]] and parameterized by a fixed key type <math>{\cal K}</math>.
# This abstract data structure is [[Genericity|generic]] and parameterized by a fixed key type <math>\mathcal{K}</math>.


== Insert at position ==
== Insert at position ==

Revision as of 09:23, 17 May 2015


General Information

Representation invariant:

  1. The abstract data structure ordered sequence implements sorted sequences as defined here.
  2. This abstract data structure is generic and parameterized by a fixed key type [math]\displaystyle{ \mathcal{K} }[/math].

Insert at position

Input: A key [math]\displaystyle{ K \in \Kappa }[/math] and a nonnegative integral position [math]\displaystyle{ p }[/math].

Output: a Boolean value, which is true if, and only if, [math]\displaystyle{ p\in\{0,\ldots,n\} }[/math], where [math]\displaystyle{ n }[/math] is the length of the list.

Precondition:

Postcondition: If the output ist true, a new element with the key [math]\displaystyle{ K }[/math] is inserted at position [math]\displaystyle{ p }[/math].

Find

Input: A key [math]\displaystyle{ K \in \kappa }[/math].

Output: A Boolean value, which is true if, and only if, [math]\displaystyle{ K }[/math] is currently contained in the sequence.

Precondition:

Postcondition:

Remove

Input: A key [math]\displaystyle{ K \in \kappa }[/math].

Output: A Boolean value, which is 'true' if, and only if, [math]\displaystyle{ K }[/math] is currently stored in the sequence.

Precondition:

Postcondition: If the output is 'true', one occurrence of [math]\displaystyle{ K }[/math] is removed.

Known Implementations

  1. Linked list
  2. Doubly-linked list
  3. Array list