can anyone help in this question?

[chief123]

sorry

[spam291203]

Any help?

[Thomas1965]

To solve this kind of problem one needs a good knowledge of algorithms and data structures.
https://www.amazon.co.uk/Guide-Competitive-Programming-Algorithms-Undergraduate/dp/3319725467/ref=sr_1_1?ie=UTF8&qid=1538914213&sr=8-1&keywords=competitive+programming

https://www.amazon.co.uk/Algorithms-Data-Structures-Competitive-Programming-ebook/dp/B078VB4HDY/ref=sr_1_3?ie=UTF8&qid=1538914213&sr=8-3&keywords=competitive+programming

[MikeyBoy]

If this is a Codechef problem, you should know that the Codechef adjudicators are aware of this forum, and that people use it to cheat on their contests. If you use this forum to try and cheat, you run the risk of being disqualified.