172. Factorial Trailing Zeroes

题目

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

Note: Your solution should be in logarithmic time complexity.

Credits: Special thanks to @ts for adding this PRoblem and creating all test cases.

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思路

计算n的阶乘的最后有几个零，就是计算因数中2和5的最小个数，5的个数肯定比2的少，就是计算因数中5的个数

代码