p172

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LeetCode p172 Factorial Trailing Zeroes 题解

1.题目：

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

Note: Your solution should be in logarithmic time complexity.

题意：

输入n输出n的阶乘的末尾有多少个0.

2.解题思路:

10=2×5
由于2比5多。所以统计因子中所有的5.

3.代码

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public class Solution {
    public int trailingZeroes(int n) {
        int ans = 0;
		while (n > 4) {
			ans = ans + n / 5;
			n = n / 5;
		}
		return ans;
    }
}

4.一些总结：