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leetcode 0172

admin 11月 13, 2020 0

Desicription

Given an integer n, return the number of trailing zeroes in n!.

Example 1:

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2
3

Input: 3
Output: 0
Explanation: 3! = 6, no trailing zero.

Example 2:

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2
3

Input: 5
Output: 1
Explanation: 5! = 120, one trailing zero.

Note: Your solution should be in logarithmic time complexity.

Solution

class  {
public:
    long long trailingZeroes(long long n) {
        long long res = 0;
        for(long long i = 5; n / i; i *= 5)
            res += n / i;
        return res;
    }
};