Given, n <= 100; now, 100! cannot be contained in ‘int’ or ‘long long’ variable. I am afraid, you need to program to multiply two numbers (stored as a ‘string’ or ‘char’ array) manually to solve the problem (or you can try with a different language, with ‘Big Integer’ library functions).

Data type ‘int’ can store 32 bits, while ‘long’ can store 64 bits. Factorial of 100 is so large that it can’t be stored even in long variable. The only way to store a large element is by array representation, ie, each digit occupies an array index.

Eg: 75337 can be represented as arr[] = {7, 5, 3, 3, 7}.