Java Program to Count trailing zeroes in factorial of a number
Last Updated :
14 Jun, 2022
Given an integer n, write a function that returns count of trailing zeroes in n!. Examples :
Input: n = 5
Output: 1
Factorial of 5 is 120 which has one trailing 0.
Input: n = 20
Output: 4
Factorial of 20 is 2432902008176640000 which has
4 trailing zeroes.
Input: n = 100
Output: 24
Trailing 0s in n! = Count of 5s in prime factors of n!
= floor(n/5) + floor(n/25) + floor(n/125) + ....
Java
import java.io.*;
class GFG {
static int findTrailingZeros( int n)
{
int count = 0 ;
for ( int i = 5 ; n / i >= 1 ; i *= 5 )
count += n / i;
return count;
}
public static void main(String[] args)
{
int n = 100 ;
System.out.println( "Count of trailing 0s in "
+ n + "! is " + findTrailingZeros(n));
}
}
|
Output:
Count of trailing 0s in 100! is 24
Time Complexity: O(log5n)
Auxiliary Space: O(1)
Please refer complete article on Count trailing zeroes in factorial of a number for more details!
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