S = database$ BWT(S) = etbda$saa
(please include some steps in your solution)
During exam, the initial values of the
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alphabets are less important. For this qn, after MTF, the last two a’s should be 2, 0.
102, 116, …, 2, 0
Pls illustrate your steps using either F & L column, or C[] and Occ.
Final answer is barbara$
2 (a) & (b) (a? bab)*
• /bib//book[year > 2000]/author always produces a subset of the result from /bib[*//year > 2000]//book/author
• As the latter can match more general cases, for example /bib//last-updated/year may contain the last update date of the entire bib database – which includes all the books.
4(a) The idea:
Your answer should consider the encoding of the XML tree into the balanced parentheses / bits:
(((()()())(()()()))(()))
You will then need to assume these parentheses are stored in blocks and explain how multi-tiered architecture as shown in ISX can e!ciently compute some navigational operations.
company department
name job salary
Use an example to illustrate how to match a sub-path on the following XBW (for simplicity, the text values are not shown here):
0E 1E 1E 0N 0J 1S 0N 0J 1S
D D 0EDC 1DC 1D
0 N EDC 0 E DC EE E0JEDC1EDC
1 S EDC 1 E DC 0NEDC 0JEDC 1SEDC 1DC
1 E DC 0NEDC 0JEDC 1SEDC 0NEDC 0JEDC 1SEDC
Start Stop Site1
(x1,s1) (y1,s3) (x4,s3) (y3,s4) Site2
(y1,s2) (z2,s3) (y1,s3) (z2,s3) (y3,s2) (z2,s3) (y3,s3) (z2,s3) Site3
(z2,s2) (x4,s3) (z2,s3) (x4,s3)
Start Result Site1
(x1,s4) x1 (x4,s4) x4 (x4,s3) x3 Site2
(y1,s4) y1 (y1,s2) y3 (y1,s3) y3 (y3,s4) y3 Site3 (z2,s1) z3 (z2,s4) z2 (z2,s2) z2 (z2,s3) z2
s1 s2 s3 s4
By tracing these two tables from (x1, s1), we obtain the final results:
y3, z2, x3, y3
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