There are only THREE countries in the entire world that have a population of more than 300 million (Facebook users). Those are China (1.33 billion), India (1.17 billion) and USA (307 million).
Convert the number to a series of 1s - so 4 becomes 1111 - and use this regex to check if it’s prime.
Very clever. Read this for an explanation.
In a recently conducted international programming contest, China topped with 20 finalists (out of 894 participants), followed by Russia with 10 finalists (out of 380 participants), and the US with 2 finalists (out of 234 participants).
India could not manage a single finalist from its 705 participants.
[The Indian bureaucracy] are a power centre in their own right at both the national and state levels, and are extremely resistant to reform that affects them or the way they go about their duties.