两个面世题 - 未名空间MITBBS历史存档

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两个面世题

两个面世题# Programming - 葵花宝典

a*y2007-06-25 07:06

1 楼

1.给你两个variable, each has one byte, multiply them, how many bytes do you
need to store the result.
2. count the number of "1" in a number. I answered use num&(num-1)来count,
他说要是worst case全是1怎么办? 我说那就count "0"是不是我说错了这个optimize的
方法?

g*g2007-06-25 07:06

2 楼

you
2
just shift to right for N times, I don't know how to beat that unless
you have a lookup table.

【在 a*******y 的大作中提到】

: 1.给你两个variable, each has one byte, multiply them, how many bytes do you
: need to store the result.
: 2. count the number of "1" in a number. I answered use num&(num-1)来count,
: 他说要是worst case全是1怎么办? 我说那就count "0"是不是我说错了这个optimize的
: 方法?