Number of 0 at the end of factorial

Add connection

Ideas ：
The problem is not to calculate n！ The result of factorial , But there are a few at the end of the factorial result 0 ！

Java Realization ：

public class Solution {
    
    public long thenumberof0 (long n) {
    
        // The result is 0 The number of is only related to 2 And 5 The number of is related to ,
        // every time 2*5 Can produce a 0. because 2 The number of must be greater than 5 The number of ,
        // So just pay attention 5 That's enough 
        if(n==0){
    
            return 0;
        }
        long r=0;
        long i=5;
        while(i<=n){
    
            r=r+n/i;//  use n Divide 5、5^2、5^3
            i=i*5;
        }
        return r;
    }
}