Stack

1
Stack

• ?????????????????????????????????????????????
  (Linear Data Structure) ?????????????????????
  ?????????????? ?????????????????????????????
  ??????????????????????????????????? ????????
  First-In Last-Out FILO

2
Stack
Push A
Push B
Over Flow
Push C
Under Flow
Pop C
Pop B
Pop A
3
Sub Program
Sub C
Sub B
Sub A
Main Program
4
Sub Program

• Main Program
• 100
• 200
• 300 Call A
• 400
• 500 Call B
• 600 Call C

Sub B 100 200 300 Call C 400 500
Sub C 100 200 300
Sub A 100 200 Call C 300
5
Stack

• Procedure PUSH(Stack, Top, MaxStk, Item)
• ??????????????????? Item ????? Stack
• If Top MaxStk Then Print Over flow and
  Return
• Set Top Top1
• Set StackTop Item
• Return.

Procedure POP(Stack, Top, Item) ?????????????????
???????? Item ??? Top ??? Stack If Top 0 Then
Print Under flow and Return Set Item
StackTop Set Top Top-1 Return.
6
Police notation

• ????????????????????????????????????????????????
  ??????????????? ??????????????????????????????????
  ?????????????? ????
• 235

Operator
Operand
Police notation ??????????????????????????????????
??????????????????????? ??????????? (Jan
Lukasiewick) ?????????????????????????????????????
?????????????
(52)3 (52)3 (52)3 523
7
Police notation
8
Police notation

• Algorithm ?????????? Infix ???? Postfix
• ??? EXP ???????????????????, Stack ???? Stack ??
  ? ???NEXP ???????????????? Postfix
• Scan ???????????????????
• ????? Operand ??????????? NEXP
• ????? ( ??? Push ???? Stack
• ????? Operator ???
• ??? Pop ??? Operator ???????? Stack ????????????
  Operator ?????????????????? NEXP ??????
• ????? Operator ????? ???????????? Stack ???
• ????? ) ???
• ??? Push ??? Operator ???????????????? NEXP
  ?????? ????????? ?? (
• Push ( ????
• ???????? 1 ???????? ? ?? ??????? EXP ???
• ???????????

9
Police notation

• ???????????????????? (10/2-2)22 ???? Postfix

10
Police notation

• Algorithm ??????????? Postfix
• Scan ???????????????????
• ????? Operand ??? Push ???????? Stack
• ????? Operator ???
• Pop ??? Operand ????? 2 ???
• ??????????????
• ????? Push ????????????????? Stack
• ???????? 1 ????????? ????? Postfix ???
• Pop ?????????????? ??? Stack ???????????????
• ???????????

11
Police notation

• ?????????????????? 10,2,/,2,-,2,,2,
  ??????????????? Postfix ????

12
Queue

• Queue ???? List ??????????? (Linear Data
  Structure) ???????????? Stack ????????????????????
  ?? Queue ???????? 2 ??? ???
• ??? (Head)
• ???? (Tail)
• ????????????????????????????????????????
  ???????? (Tail) ???Queue ???????????? (Head) ???
  Queue ???? Queue ?????????????????????? ????????
  ??????? (First-In First-Out FIFO)

Head
Tail
13
Queue
Delete A
H
T
H
T
Insert A
Delete B
H
T
H
T
Insert B
Insert A
Queue Overflow
H
T
Insert C
Delete C
H
T
H
T
Queue Overflow
Insert D
Delete A
Queue Underflow
14
Circular Queue
Delete A
H
T
H
T
Insert A
Delete B
H
T
H
T
Insert B
Insert A
H
T
H
T
Insert C
Insert B
H
T
H
T
Queue Overflow
Insert D
15
Priority Queue

• ???? Queue ???????????????????????????????????????
  ??????????
• ??????????????????????????????????????????????????
  
• ????????????????????????????????????????
  ??????????????????????????????????????