2006北京市小学生信息奥赛参考答案

2006年北京市小学生信息奥赛参考答案

1． 今年是哪年year.bas

考点：空格函数spc(n)

OPEN "year.in" FOR INPUT AS #1

OPEN "year.out" FOR OUTPUT AS #2

DIM n AS LONG

INPUT #1, n

PRINT #2, LTRIM$(STR$(2)); SPC(n);

PRINT #2, LTRIM$(STR$(0)); SPC(n);

PRINT #2, LTRIM$(STR$(0)); SPC(n);

PRINT #2, LTRIM$(STR$(6));

CLOSE

END

考点：

2． 方便游客lanche.bas

考点：数学归纳+累加求和

OPEN "lanche.in" FOR INPUT AS #1

OPEN "lanche.out" FOR OUTPUT AS #2

DIM i AS LONG , n AS LONG， sum AS LONG

sum = 0

INPUT #1, n

FOR i = 1 TO n - 1

sum = sum + i

NEXT i

PRINT #2, LTRIM$(STR$(sum))

CLOSE

END

3． 总留空时间 time.bas

考点：最大值和最小值（打擂台思想）或 排序方法

OPEN "time.in" FOR INPUT AS #1

OPEN "time.out" FOR OUTPUT AS #2

DIM n, as long, i as long , l as long ,r as long , min as long ,max as long , time as long INPUT #1, n

INPUT #1, l, r

min = l

max = r

FOR i = 2 TO n

INPUT #1, l, r

IF l < min THEN min = l

IF r > max THEN max = r

NEXT i

time = max - min

PRINT #2, LTRIM$(STR$(time))

CLOSE

END

2006年北京市小学生信息奥赛参考答案

4． 统计质数prime.bas

考点：质数，判断质数方法：2到开平方内无约数！

OPEN "prime.in" FOR INPUT AS #1

OPEN "prime.out" FOR OUTPUT AS #2

DIM i, as long ,m as long ,n as long ,cs as long , js as long

cs = 0

js=0

INPUT #1, m, n

FOR i = m TO n

Js=0

FOR j = 2 TO sqr(i)

IF i MOD j = 0 THEN

Js=js+1

END IF

NEXT j

IF js=0 and i <>1THEN

cs = cs + 1

END IF

NEXT i

PRINT #2, LTRIM$(STR$(cs))

CLOSE

END

5．divi.bas

考点：模拟除法过程，被除数由余数放大10倍，除数永远为113，求商，小数点后的第n位为整个商的第n+1位。

OPEN "divi.in" FOR INPUT AS #1

OPEN "divi.out" FOR OUTPUT AS #2

DIM i AS LONG, n as long

DIM shang AS DOUBLE yu as double, bei as double

INPUT #1, n

bei = 355

FOR i = 1 TO n+1

shang = bei \ 113

yu = bei MOD 113

bei = yu * 10

NEXT i

PRINT #2, LTRIM$(STR$(shang))

CLOSE

END

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