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spreered/is_power_of_two_1.rb Secret

Last active September 13, 2017 05:59
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Power of Two
Raw
is_power_of_two_1.rb
def is_power_of_two(n)
return false if n<=0
while n>1
return false if n % 2 ==1
n = n/2
end
true
end
Raw
is_power_of_two_2.rb
#使用二進位判斷
#如果n是2的次方 2進位表示一定為 1000....00
#n-1則為0111....11
# and(&) 後結果一定是0
def is_power_of_two(n)
n > 0 && (n & (n-1) == 0)
end
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