4, the implementation of the stack: sequential storage and chain storage

ADT for Stack:

1  Packageren.laughing.datastructure.base;2 3 Importren.laughing.datastructure.exception.StackEmptyException;4 5 /**6 * Stack stack: LIFO7 * can only be inserted (into the stack), delete (stack) operation on top of the stack8  * @authorLaughing_lz9 * @time April 6, 2016Ten  */ One  Public InterfaceStack { A     //returns the size of the stack -      Public intgetsize (); -     //determine if the stack is empty the      Public BooleanisEmpty (); -     //data element e into the stack -      Public voidpush (Object e); -     //stack top element out stack +      PublicObject pop ()throwsstackemptyexception; -     //take the top element of the stack +      PublicObject Peek ()throwsstackemptyexception; A}

Sequential storage of Stacks:

1  PackageRen.laughing.datastructure.baseImpl;2 3 ImportRen.laughing.datastructure.base.Stack;4 Importren.laughing.datastructure.exception.StackEmptyException;5 /**6 * Sequential storage structure of stacks7 * Generally, you should not set the stack's maximum capacity when constructing the stack. 8 * A reasonable practice is to first allocate a basic capacity for the stack, and then in the actual use of the process,9 * When there is not enough space on the stack to multiply the storage space, the time required for this process is halved to each numberTen * The element time is θ (1), which does not affect the time complexity of the operation implementation.  One  * @authorLaughing_lz A * @time April 6, 2016 -  */ -  Public classStackarrayImplementsStack { the     Private Final intLEN = 8;//storage size of default array -     PrivateObject[] elements;//array of data elements -     Private intTop//stack Top pointer -      +      PublicStackarray () { -          This. elements =NewObject[len]; +          This. top =-1;//when top is-1 indicates an empty stack A     } at  - @Override -      Public intGetSize () { -         returnTop+1; -     } -  in @Override -      Public BooleanIsEmpty () { to         if(Top < 0){ +             return true; -}Else{ the             return false; *         } $     }Panax Notoginseng  - @Override the      Public voidpush (Object e) { +         if(GetSize () >=elements.length) { A expandspace (); the         } +         //++top: Because the stack operation is equivalent to InsertAfter, -         //can only be inserted after the vertex, so first add 1 to the top and then the data element $Elements[++top] =e; $     } -  - @Override the      PublicObject pop ()throwsstackemptyexception { -         if(top<0){Wuyi             Throw NewStackemptyexception ("Error: Stack is empty, no stack operation"); the}Else{ -Object obj =Elements[top]; Wuelements[top--] =NULL;//first remove the original stack top data element, then empty, top minus one -             returnobj; About         } $     } -     //take the top element of the stack - @Override -      PublicObject Peek ()throwsstackemptyexception { A         if(GetSize () <=0){ +             Throw NewStackemptyexception ("Error: Empty stack top"); the}Else{ -             returnElements[top]; $         } the     } the     /** the * Extended Array length the      */ -     Private voidExpandspace () { inObject[] A =NewObject[elements.length * 2]; the          for(inti = 0; i < elements.length; i++) theA[i] =Elements[i]; Aboutelements =A; the     } the}

Chained storage for Stacks:

1  PackageRen.laughing.datastructure.baseImpl;2 3 ImportRen.laughing.datastructure.base.Stack;4 Importren.laughing.datastructure.exception.StackEmptyException;5 /**6 * Stack-chained storage7 *★ A single-linked list with no head nodes for this list8  * @authorLaughing_lz9 * @time April 6, 2016Ten  */ One  Public classStacklinkedImplementsstack{ A     PrivateSlnode top;//link List First node reference -     Private intSize//the size of the stack -      the      Publicstacklinked () { -          This. Size = 0; - //this.top = new Slnode (null, NULL); -top =NULL;//is this also instantiated? Is there any difference from the above?  +     } -  + @Override A      Public intGetSize () { at         returnsize; -     } -  - @Override -      Public BooleanIsEmpty () { -         returnSize==0; in     } -      to @Override +      Public voidpush (Object e) { -Slnode node =NewSlnode (E, top);//equivalent to insertbefore inserting a new data element before the top of the original stack thetop =node; *size++; $     }Panax Notoginseng  - @Override the      PublicObject pop ()throwsstackemptyexception { +         if(size<=0){ A             Throw NewStackemptyexception ("Error, stack is empty. "); the         } +Object obj =Top.getdata (); -top =Top.getnext (); $size--; $         returnobj; -     } -  the @Override -      PublicObject Peek ()throwsstackemptyexception {Wuyi         if(size<=0){ the             Throw NewStackemptyexception ("Error, stack is empty. "); -         } WuObject obj =Top.getdata (); -         returnobj; About     } $  -}

4, the implementation of the stack: sequential storage and chain storage