Problem:
n! means n × (n − 1) × ... × 3 × 2 × 1 For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800, and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27. Find the sum of the digits in the number 100! My Solution:
Note: You can simplifies the coding :)
n! means n × (n − 1) × ... × 3 × 2 × 1 For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800, and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27. Find the sum of the digits in the number 100! My Solution:
static void Main(string[] args)
{
BigInteger multi = 1;
long result = 0;
int digits = 100;
for (int i = digits; i >= 1; i--)
{
multi *= i;
}
foreach (var item in multi.ToString().ToCharArray())
{
result += long.Parse(item.ToString());
}
Console.WriteLine(result);
Console.ReadLine();
}
Note: You can simplifies the coding :)
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