Basic Data Structures

Stack-empty (S)
If s.top = = 0
Return TRUE
else return FALSE

PUSH (s,x)
S.top = s.top + 1
S[s.top] = X

POP (S)
If Stack-empty (S)
Error "Underflow"
else S.top = s.top-1
return s[s.top+1]

Queue
INSERT, ENQUEUE
DELETE, DEQUEUE

ENQUEUE (q,x)
Q[q.tail]=x
if Q.tail = = Q.length
Q.tail = 1
else Q.tail = q.tail + 1

DEQUEUE (q.x)
x = Q[q.head]
if (Q.head = = q.length)
Q.head = 1
else Q.head = q.head + 1
return x

Linked list, doubly linked list, unidirectional linked list, circular link list
List-search (L,k)
x = L.head
While x! = NULL and X.key! = k
x = X.next
return x

List-insert (l,x)
X.next = L.head
If l.head! = NIL
L.head.prev = X
L.head = X
X.prev = NIL

List-delete (l,x)
If X.prev! = NIL
X.prev.next = X.next
else L.head = X.next
If X.next! = NIL
X.next.prev = X.prev

Sentinel
List-search (L, K)
x = L.nil.next
While x! = L.nil and X.key! = k
x = X.next
return x

List-insert (l,x)
X.next = L.nil.next
L.nil.next.prev = X
L.nil.next = X
X.prev = L.nil

Pointers and Object implementations

Objects and most groups represent

object and singular group representations

Allocation and release of objects

Suppose that the array length in most group notation is M, and the dynamic collection contains n<=m elements at a given moment. n objects represent the existing dynamic
The elements in the collection, while the remaining M-n objects are free, and these free objects can be used to represent the elements to be inserted into the dynamic collection

Free Form
Allocate-object ()
If free = NIL
Error "Out of space"
else x = Free
Free = Free.next
return x

Free-object (x)
X.next = Free
Free = X

Multi-linked list majority group notation

Basic Data Structures