Q:

Time Complexity - nested for loop

For the given code, whats the time complexity in bigO notation:
for(i=n; i >= 1; i /=2)
 for(j=i; j>=1; j/=2)
     x = i+j;

The first loop runs Log N times, how about the second loop? 
Is it (Log N * Log N) ? 
I am confused. 
Thanks

A:

Asymptotically, we can say that complexity of second loop is O(logn) and  In each iteration of first Loop, second loop iterates once, so the complexity will be logn*logn that is (logn)^2

