There are many times during my degree where I heard my friends, and professors, describe group theory, number theory, combinatorics, etc. as directly pertinent in application to computer science.
I do consider this a valid perspective, no question.
However, I have also heard that analysis does not directly pertain to computer science by many of the same people.
This I do take issue with. After having completed both group theory and introduction to analysis, I found both equally with merit.
This post aims to describe their resepctive merits.