Thank you for your comment. Most of the solutions indeed take less than a minute. Solution to problem 1 & 3 took 25 sec and that to 5 took 26.
The solution that took 9 minutes involved processing the abstract in each record. The abstracts are quite sizeable on some of these publications. Processing millions of them took time.
The solution that took 48 minutes involved a nested loop effectively reaching the iteration count for 216 years times 256M records which comes to about 55B.
Hope this clarifies things a bit but I am not claiming this to be the most optimized solution. I am sure there is scope for refinements -- this was my take on it.
The solution that took 9 minutes involved processing the abstract in each record. The abstracts are quite sizeable on some of these publications. Processing millions of them took time.
The solution that took 48 minutes involved a nested loop effectively reaching the iteration count for 216 years times 256M records which comes to about 55B.
Hope this clarifies things a bit but I am not claiming this to be the most optimized solution. I am sure there is scope for refinements -- this was my take on it.