Back here with some more doubts, i wanted to understand, how can we formally or may be easily calculate time complexity for such question without getting into "DRY RUN", i mean is there any way for it? and for below question i am getting O(loglog(n/2)) which is not right!
Thankyou in advance for sharing your wisdom :)
The inner loop executes $\dfrac{n-j}2$ times, and the middle loop processes $j=n,\dfrac n2,\dfrac n4,\cdots$
This makes a total that is very close to $\dfrac{n\lg(n)}2-n$.
The outer loop repeats this $\lg(n)$ times, for a grand total of
$$\left(\dfrac{n\lg(n)}2-n\right)\lg(n)$$
which is asymptotically $O(n\log^2(n)).$