Factorial Trailing Zeroes Given an integer n, return the number of trailing zeroes in n!.
Note that n! = n * (n - 1) * (n - 2) * ... * 3 * 2 * 1.
Example 1:
Input: n = 3 Output: 0 Explanation: 3! = 6, no trailing zero.
Example 2:
Input: n = 5 Output: 1 Explanation: 5! = 120, one trailing zero.
Example 3:
Input: n = 0 Output: 0
Constraints:
0 <= n <= 104
Factorial Trailing Zeroes Solutions
✅Time: O(log n)
✅Space: O(1)
C++
class Solution {
public:
int trailingZeroes(int n) {
return n == 0 ? 0 : n / 5 + trailingZeroes(n / 5);
}
};
Java
class Solution {
public int trailingZeroes(int n) {
return n == 0 ? 0 : n / 5 + trailingZeroes(n / 5);
}
}
Python
class Solution:
def trailingZeroes(self, n: int) -> int:
return 0 if n == 0 else n // 5 + self.trailingZeroes(n // 5)
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