There is a course called CS207 Discrete Structures taught by Professor Ajit Diwan. It was related to Discrete Mathematics - Number Theory, Graph Theory, Combinatorics, Sets, and Groups, and was one of the most difficult courses my friend came across.
Professor Diwan is well known for his highly challenging problems and course material. During his lectures, he delivers a lot of information based on principles. For math lovers, his classes are an absolute delight.
He refrains from conducting more than one exam a month. However, the level of difficulty of the exam is high. The questions look very complicated but when one ponders upon them, they don’t seem that difficult.
The exams were extremely difficult to the extent that the passing cutoff was 7 out of 100 marks. Despite the entire batch consisting of JEE toppers, a lot of them were not able to make it to the cutoff.