1990-11-03 — Page 30

育教:日七十月九年午庚醫菱

月一十(〇九九一)年九十七國民華中

津校聘文員

灣仔區中學聘交員中學畢業懂打 字識中文電腦打字更佳有意請於 辦公時間電五二七二四二六孔小 姐洽。

B

1991 中學會考預習專欄:

明濺出版社

MILL & DALE PRESS

報日僑華

六期星 日三月一十(〇九九一)年九十七國民華中( 30 )

Discussions : (1) The values stored in the array A(1), (2), 4(11] | Exercise on flowchart tracing:

Computer (5)

Search: to Fook for the existence of a particular character string a sorted sequence.

Gary search method is a systematic way to search.

Algorithm

K. Choy

fat cook for the middle term. If there are n terms in the sequence, the position of the mid-term can be calculated by

Sum of the positions of start and end term

(b) Compare the selected middle to with the particular

number to be search,

Discard the upper hal(including the mid- term) if the nimiter is less than the mid-term. til Discord the lower half (including: the mid- term if the number is greater than the mid- term, b

Di) The term is found at the position if both

numbers are equal.

(d) The above three steps are repeated until the last

umber remained is compared.

(e) if the number is not found for the whole search

Jrocess, the number is not fo the array,

are covered.

Figure 1 is a flowchart of binary search. Suppose there áre (2) Steps (a), (b) and (c) are repeated until the end 10 elements in Bscending order an array,

of the list.

MIT=6, R(2) =7, (3) 15, (N[4). 12, N(S) N(7) 37, N(8) 64 (9) (3) At each round, half of the terms in the remaining(5) "24, N(7)

list are discarded because we are certain that the and is the number to be looked for Complete the following Humber would not turn up in this half as the terms tables. (A round means the oup between boxes 5 and 10)

are arranged in ascencing ander.

(11) Similar steps are used to locate the position of 160,

(6) A(7) 4(8) A(9)|A(19)|A(1) 110

A(1) 4(2)

( terms).

Number to be looked for: K = 24

·ROUND

Start

N(T)

LOW

HIGH [LOW>HIGH}

10.

10-160

A(7) A(8) A(9) A10) A11)

159

(5 tews Teft)

What is the printed output?

115970160

{A(10) {A(11)

300

(2 terns left) (11) Number to be looked for:

ROUND

I

N(1) LOW

HIGH

LOW HIGH

300 160

lements to the fist dan discarded.. in the list

Not found

160

Start

1.

2

ATL

SEART

Example: Suppose there is a sorted array of eleven number

numbers stored are

The

21, 36, 47, 99 104, BED, 199,

159 300, 310.-

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If the numbers are covered and we cannot see the values Search for the existence of (1) 10:and (51) 160.

急聘下列空欲,

登記護士:年齡30歲以下持有香港護士局登記 LIB

Position [1]]

„Number,

41 99

:10 144 145

*級物理治療師(全職或兼職、

上述職位薪金被政府編制交通津貼免費醫艉應徵 者請來防元朗廈村屏廈路青松贌理安老院或電 4721393'與周小姐

mid-tere position

-ih tere

6th

Campare the value

43:1013110, the elements after e(3) discorpád,

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下列學位或非學位教師

1.英文及經公!十二月上任)

2.歷史及英文(二月上任)

*有意請函履歷相片寄華僑日報信箱

1771 號

小學教師

·九龍西、荃灣區私立英小誠聘

1991 1100

Mid-term position

Compary, the valud

As 101

to approach the 45th kerm

integral part is taken as 4th terf

Lue stored in A(4) Menta) 101.

ghts before A44] is discarded...

知

Mia-term position = 5

5ta term.

Compare the valus stongd in 3(5) with

101 is found at the 20h posit

教師政府薪酬福利佳,請電 7422027洽

nave p

1991 中學會考臻習專欄

政府資中急聘

物理教師(學位)

H=10:

the printed outout)

(iii) from the above example, to search e number in an array of 10

elements, there are at most 4 trials (rounds)

whats the number of trials at cost if an array.com elements?

(1) Number to be looked for

RUDNU

共圖

Start

2

64

N(T) LOW:

HIGH LOWSHIGH

10

Yes

output. "The number is at 6th position,

Number

ROUND

Start

iba inaked for X18

LOW: HIGH

LOWSHIGH

From: (1)

LIBR

明連出版衣

MILL & DALE PRESS

Mathematics (5)

KONG

Fxercise 5: Simultaneous Equations.

Section A

Solve the system of equations

equations.

Sucstitute 13) into (2)

When

.7071-

1.7071

G PUBLIC

upsritute (3) into (2)

-647 (bx+13)(x-1)

2560

有意請電 3412932

單小姐洽

Sölve

急聘學位教師

沙山津中誠聘英文學位教師十二月 封職,負責中四至中六英文科,生 低年級經公及英文學位教師,有經 驗或退休教師亦可申請臨時職位,工

6488662

青衣區幼稚園

誠聘幼師

DEA (ER4)

ABY 634560.

Tve the system

lbys

system of equations

Solva, the system of equati

Solve the system, of aquations

2)助教(學程胤,有留升機會)

| (x+2) + 3(y+3)

入職薪金$3760

有意請電 4955595

The numbers NOT the

If on gray contains 20

trounds)

speed

the dis!

56w#11

CL0.29291

#7071 1.4393

unstitute.

5606

+(40-307

200

Euns:

Subs

Anto (1) 1616x)?

Lonsider

Substitute (3) into (1)

1208

-0.208 -0,208 -1.249

Pinta (1):

金工科兼實用科學科

學位或文憑教師

荃灣津貼職業先修中學誠聘金工 兼實用科學科學位或文憑敎師有 意者請電 4121899 約見

Section N

If the aquations 5x+7-6-0, 3x-y+4=0° and (p+1}x-8y+1=0 are all satisfied.

simultaneously by one pair of x and.

Find the value of p.

A man travels from A to

ato

unt form speed, "If he increases his speed by 1km per hour the journey will take 11 hours less. If ne roduces his speed by km per hour. It will take 2 hours 5 minutes more. Find the distance betwear A and 8,

If 3x+4y=k is tangent of the circle, x2+y2-26 where K constant. Find K,

13y* 30y 390

304 VB0RKIN

-30±54 11 26

-3.235

-3.236 31-32235)+5

When y = 0.927

3.891

and

-3.891 9.927

+363 3.236

(Ans.)

when

Section B

(Ansi)

10,

the distance between and

400

1.6x

6kx

9x2 - 400

25x

6kx

Since it is a.

ngent, there:

only ONE root:

(-Ek)2 - 4(25)(K2-400); = 0

40000

0

-25

(Ans.)

..(2)

1.25

Substitute into (2)"

-0.25 Substitute the values

(p-1/11.25)-8(-0.25)+5=0

From which

Substitute (2) Toto (1)

x4 - 6x + (4-k) = 0

For no real solution,

B4ACCO

36 2.16 * 4k 3-0

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