I am working on a problem on codeforce. I came up with a method but it solves down to a formula which is $ \frac{n!}{w!r!}, ! $ stands for factorials of number. How can I work such problems out? asked 11 Jul, 03:32

In any of problem if situation comes to compute the value of $nCr$ then the contraints are set such that we can iterate over the smaller of the two factorials in denominator and compute the answer. And if we are required to calculate the value for large constraints then we must have given some modulo number and in that case we can compute the factorial of all the number and then take inverse modulo for the denominator (if the given modulo number is prime. In case it is not then we have to do a little bit of extra work.) For code you can refer this : https://cpalgorithms.com/combinatorics/binomialcoefficients.html inverse modulus : https://www.quora.com/HowdoIfindthevalueofnCr1000000007forthelargenumbernn106inC answered 11 Jul, 17:51

U can also go with method stated by @pk301 answered 11 Jul, 20:01

How to work means ? What u wanna ask ? Share the problem link for more help...
It's not a specific problem. It is just like I want to calculate the formula, knowing that it will reduce to some simple natural number. Like $ \frac{10!}{6!2!} $
but u r working on a problem of CF right... so I was asking for that question link..