Showing run error

#1
#2

hello @anubhavb11
100! factorial is a very big number and we cant store it in any datatype .

thats why we will use array to store that big number.
here is the logic->
factorial(n)

  1. Create an array ‘res[]’ of MAX size where MAX is number of maximum digits in output.
  2. Initialize value stored in ‘res[]’ as 1 and initialize ‘res_size’ (size of ‘res[]’) as 1.
  3. Do following for all numbers from x = 2 to n.
    ……a) Multiply x with res[] and update res[] and res_size to store the multiplication result.

How to multiply a number ‘x’ with the number stored in res[]?
The idea is to use simple school mathematics. We one by one multiply x with every digit of res[]. The important point to note here is digits are multiplied from rightmost digit to leftmost digit. If we store digits in same order in res[], then it becomes difficult to update res[] without extra space. That is why res[] is maintained in reverse way, i.e., digits from right to left are stored.

multiply(res[], x)

  1. Initialize carry as 0.
  2. Do following for i = 0 to res_size – 1
    ….a) Find value of res[i] * x + carry. Let this value be prod.
    ….b) Update res[i] by storing last digit of prod in it.
    ….c) Update carry by storing remaining digits in carry.
  3. Put all digits of carry in res[] and increase res_size by number of digits in carry.
#3

is there any video on it i really not able to understand the logic

#4

search on utube ,it is very famous problem

#5

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