Approach
Written by Hanyuan Li from CSESoc Competitions
The question itself isn't too difficult to wrap your head around, the main difficulty is in the implementation. Below are some things to keep in mind as you are implementing your solution:
Finding whether a number is prime or not
From Wikipedia:
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers.
In order to figure out whether a number is prime or not, we can check whether it's
divisible by all natural numbers smaller than it (except for 1). We can do that with
a while loop from 2 all the way up to our target number, and use the % operator
to check for the modulus (or "remainder") when we divide our target number by any
smaller number.
Room 2 point splitting
In Room 2, points are split based on the amount of points each player has already won. This means you need to keep track of everyone's points throughout the game, as that information becomes important once players step into that room specifically (and when we output the scores for each player). In order to calculate each player's specific share of points, we can calculate the portion of points they're supposed to get by dividing their score by the sum of the scores of every player that stepped into the room.
Rounding
In C, the round function exists to help you round a floating-point integer to a
certain number of decimal places. It is located in the <math.h> library, so you
will need to #include that at the top of your program.
round takes two arguments, your floating-point variable and the number of digits
you want to round to. For example:
round(1.444, 2) // becomes 1.44round(1.75, 1) // becomes 1.8