剑指OFFER----面试题14- II. 剪绳子II

链接：https://leetcode-cn.com/problems/jian-sheng-zi-ii-lcof/

代码：

class Solution {
public:
    int cuttingRope(int n) {
        if(n < 4) return n - 1;
        long res = 1;
        while(n > 4) {
            res *= 3;
            res %= 1000000007;
            n -= 3;
        }
        return res * n % 1000000007;
    }
};