0  1  2  3  4  5  6  7  8  9 
ch	   A     B        A  C  D
next1	5  2  3  4  8  6  7  8  9  0
next2	5  2  1  4  8  2  7  8  9  0
______________________________________
(A*B+AC)D

         6    7
      /--A----C----\
  5  /              \
--o--\               \   9
      \               D--*
    1  \2       3   4 |
    A---o-------B---o--
    |___|
______________________________________
a = "AAABD"
______________________________________		dq
int match(char *a)
1:
scan =-1, N=strlen(a)=5, j = 0, 
state=next1[0]=5,
Deque dq;	

start while (state) {				-1
ch[state=5]=' '
	n1=next1[state=5]=6		________________
	n2=next2[state=5]=2			2
	dq.push(n1)				6
	dq.push(n2)				-1
state=dq.pop()=2			________________
						1
2:						3
ch[state=2]=' '					6
	n1=next1[state=2]=3			-1
	n2=next2[state=2]=1			
	push(n1), push(n2)
state=dq.pop()=1			________________

3:						3
ch[state=1]='A'=a[j=0]				6
	dq.put(next1[state=1]=2)		-1
state=dq.pop()=3				2
					________________
4:						6
ch[state=3]='B' != a[j=0]='A'			-1
state=dq.pop()=6				2
					________________
5:						-1
ch[state=6]='A'=a[j=0]				2
	dq.put(next1[state=6]=7)		7
state=dq.pop()=-1			________________

6:						2
state == scan					7
	j++=1					-1
	dq.put(scan=-1)			________________
state=dq.pop()=2
						1
7:						3
ch[state=2]=' '					7
	n1=next1[state=2]=3			-1
	n2=next2[state=2]=1			
	push(n1), push(n2)		________________
state=dq.pop()=1				3
						7
8:						-1
ch[state=1]='A'=a[j=1]				2
	dq.put(next1[state=1]=2)	________________			
state=dq.pop()=3
						7
9:						-1
ch[state=3]='B' != a[j=1]='A'			2
state=dq.pop()=7			________________

10:						-1
ch[state=7]='C' != a[j=1]='A'			2
state=dq.pop()=-1			________________	

11:
state == scan					2
	j++=2					-1
	dq.put(scan=-1)			________________
state = dq.pop()=2

12:						1
ch[state=2]=' '					3
	n1=next1[state=2]=3			-1
	n2=next2[state=2]=1		________________
	push(n1),push(n2)		
state=dq.pop()=1
						3
13:						-1
ch[state=1]='A'=a[j=2]				2
	dq.put(next1[state=1]=2)	________________	
state=dq.pop()=3			

14:						-1
ch[state=3]='B' != a[j=2]='A'			2
state=dq.pop()=-1			________________				
					
15:						2
state == scan					-1
	j++=3				________________		
	dq.put(scan=-1)
state=dq.pop()=2

16:						1
ch[state=2]=' '					3
	n1=next1[state=2]=3			-1
	n2=next2[state=2]=1		________________
	push(n1),push(n2)
state=dq.pop()=1
						3
17:						-1
ch[state=1]='A' != a[j=3]='B'		________________
state=dq.pop()=3

18:						-1
ch[state=3]='B' = a[j=3]			4
	dq.put(next1[state=3]=4)	________________
state=dq.pop()=-1
						4
19:						-1
state == scan				
	j++=4				
	dq.put(scan=-1)			________________
state=dq.pop()=4

20:
ch[state=4]=' '					8
	n1=next1[state=4]=8			-1
	n2=next2[state=4]=8
	push(n1)			________________
state=dq.pop()=8
						-1
21:						9
ch[state=8]='D' = a[j=4]		
	dq.put(next1[state=8]=9)	________________
state=dq.pop()=-1

22:
state == scan					
	j++=5					9
	dq.put(scan=-1)				-1
state=dq.pop()=9			________________

23:
ch[state=9]=' '					-1
	n1=next1[state=9]=0			0
	n2=next2[state=9]=0
	push(n1)			________________
state=dq.pop()=-1

24:
state == scan					0
	j++=6					-1
	dq.put(scan=-1)
state=dq.pop()=0			________________

} end while (state)