C ++：这些按位与与随后的比较有什么作用？

Question

I'm currently going through this implementation of finding a median using two heaps: No. 30 - Median in Stream

I understand the general basic algorithm, but I'm not sure how this exact implementation works. Specifically, I'm absolutely confused what these two lines do:

if(((minHeap.size() + maxHeap.size()) & 1) == 0)
....
if(size & 1 == 1)

I believe I understand the bitwise AND- it takes the two numbers and outputs a number in binary. With the comparison of == 0 or == 1, it would check literally if the bitwise AND comes out with a 0 or a 1, respectively. However, in the context of finding the median, what does this exactly do? I know it's important for keeping the heaps "even" (and keeping the median in between the two heaps), but other than that I'm not entirely sure. Is this really just a way to check if the sizes are different?

Answer 1

I believe the first test is true if lowest bit is zero, ie sum is even number. The second test is true if size is odd number (ie LSB is set).