I have two questions about big-oh expression.

The first one is:

for(i=1;i<n;++i)

for(j=1;j<floor(i/2);j++)

{

...statements that require exactly j operations...

};

For this one, i think that the number of operations written by big-oh operations is O(n^2)

for (i=1;i<n;++i)

{

...statements that require at most 10^9 /i operations

}

For this one, i do not understand the meaning of "at most 10^9 /i operations". Hope someone give me some suggestions. Thx.